Methods, Compositions and Articles of Manufacture for Enhancing Survivability of Cells, Tissues, Organs, and Organisms

ABSTRACT

The present invention concerns the use of oxygen antagonists and other active compounds for inducing stasis or pre-stasis in cells, tissues, and/or organs in vivo or in an organism overall, in addition to enhancing their survivability. It includes compositions, methods, articles of manufacture and apparatuses for enhancing survivability and for achieving stasis or pre-stasis in any of these biological materials, so as to preserve and/or protect them. In specific embodiments, there are also therapeutic methods and apparatuses for organ transplantation, hyperthermia, wound healing, hemorrhagic shock, cardioplegia for bypass surgery, neurodegeneration, hypothermia, and cancer using the active compounds described.

This application is related to U.S. Provisional Patent Applications60/673,037 and 60/673,295 both filed on Apr. 20, 2005, as well as U.S.Provisional Patent Application 60/713,073, filed Aug. 31, 2005, U.S.Provisional Patent Application 60/731,549, filed Oct. 28, 2005, and U.S.Provisional Patent Application 60/762,462, filed on Jan. 26, 2006, allof which are hereby incorporated by reference in their entirety.

The government may own rights in the present invention pursuant to grantnumber GM048435 from the National Institute of General Medical Sciences(NIGMS).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of cell biology andphysiology. More particularly, it concerns methods, compositions andapparatuses for enhancing survivability of and/or reducing damage tocells, tissues, organs, and organisms, particularly under adverseconditions, including but not limited to hypoxic or anoxic states, usingone or more substances, including those that compete with oxygen. Incertain embodiments, the present invention includes methods,compositions and apparatuses for treating, preventing, and diagnosingdiseases and conditions by exposing a subject to an oxygen antagonist,protective metabolic agent, or other chemical compound discussed herein,or a precursor thereof, that can achieve its stated goal (collectivelyreferred to as “active compounds”).

2. Description of Related Art

Stasis is a Latin term meaning “standstill.” In the context of stasis inliving tissues, the most common forms of stasis relate to thepreservation of tissues for transplant or reattachment. Typically, suchtissues are immersed in a physiologic fluid, such as saline, and placedin the cold to reduce biochemical processes leading to cellular damage.This stasis is incomplete and cannot be relied upon for extendedperiods. In fact, the success of organ transplant and limb reattachmentis inversely related to the time the organ or limb is out of contactwith the intact organism.

A more extreme version of stasis involves placing an entire organisminto what is known colloquially as “suspended animation.” Though stillconsidered largely within the realm of science fiction, some notorietyhas been achieved when wealthy individuals have sought to becryopreserved after death, in the hope that future medical breakthroughswill permit their revival and cure of their fatal ailments. Allegedly,more than one hundred people have been cryopreserved since the firstattempt in 1967, and more than one thousand people have made legal andfinancial arrangements for cryonics with one of several organizations,for example, Alcor Life Extension Foundation. Such methods involve theadministration of anti-ischemic drugs, low temperature preservation, andmethods to perfuse whole organisms with cryosuspension fluids. It hasnot yet been substantiated that this form of organismal stasis isreversible.

The utility of inducing stasis in biological matter as contemplated bythe compositions, methods, or articles of manufacture described herein,is characterized by induction or onset of stasis followed by a period oftime in which the stasis is maintained, followed then by reversion to anormal or near normal physiological state, or a state that one skilledin the art would recognize as a state that is better than the state ofthe biological matter had it never undergone stasis, in whole or inpart. Stasis can also be defined as what it is not. Organismal stasis isnot any of the following states: sleep, comatose, death, anesthetized,or grand mal seizure.

There are numerous reports of individuals who have survived apparentcessation of pulse and respiration after exposure to hypothermicconditions, usually in cold-water immersion. Though not fully understoodby scientists, the ability to survive such situations likely derivesfrom what is called the “mammalian diving reflex.” This reflex isbelieved to stimulate the vagal nervous system, which controls thelungs, heart, larynx and esophagus, in order to protect vital organs.Presumably, cold-water stimulation of nerve receptors on the skin causesshunting of blood to the brain and to the heart, and away from the skin,the gastro-intestinal tract and extremities. At the same time, aprotective reflex bradycardia, or slowing of the heart beat, conservesthe dwindling oxygen supplies within the body. Unfortunately, theexpression of this reflex is not the same in all people, and is believedto be a factor in only 10-20% percent of cold-water immersion cases.

Compositions and methods that do not rely fully or at all on hypothermiaand/or oxygen may be useful in the context of organ preservation, aswell as for tissue or cell preservation. Cells and tissue are currentlypreserved using hypothermia, frequently at temperatures substantiallybelow freezing, such as in liquid nitrogen. However, dependence ontemperature can be problematic, as apparatuses and agents for producingsuch low temperatures may not be readily available when needed or theymay require replacement. For example, tissue culture cells are oftenstored for periods of time in tanks that hold liquid nitrogen; however,these tanks frequently require that the liquid nitrogen in the unit beperiodically replaced, otherwise it becomes depleted and the temperatureis not maintained. Furthermore, damage to cells and tissue occurs as aresult of the freeze/thaw process. Thus, improved techniques are needed.

Moreover, the lack of ability to control cellular and physiologicmetabolism in whole organisms subjected to traumas such as amputationand hypothermia is a key shortcoming in the medical field. On the otherhand, the anecdotal evidence discussed above strongly suggests that ifproperly understood and regulated, it is possible to induce stasis incells, tissues and whole organisms. Thus, there is a great need forimproved methods for controlling metabolic processes particularly undertraumatic conditions.

SUMMARY OF THE INVENTION

Therefore, the present invention provides methods, compositions,articles of manufacture, and apparatuses to induce stasis in cells,tissues and organs located within or derived from an organism, as wellas in the organism itself. Such methods, compositions, articles ofmanufacture, and apparatuses can be employed to protect biologicalmatter, as well as to prevent, treat, or diagnose diseases andconditions in the organism. In addition, such methods may directlyinduce stasis themselves, or they may act indirectly by not inducingstasis themselves, but by enhancing the ability of biological matter toenter stasis in response to an injury or disease condition, e.g., byreducing the time or level of injury or disease required to achievestasis. Such a condition may be referred to as pre-stasis. Details ofsuch applications and other uses are described below.

The invention is based, in part, on studies with compounds that weredetermined to have a protective function, and thus, serve as protectiveagents. Moreover, the overall results of studies involving differentcompounds indicate that compounds with an available electron donorcenter are particularly effective in inducing stasis or pre-stasis. Inaddition, these compounds induce reversible stasis, meaning they are notso toxic to the particular biologic matter that the matter dies ordecomposes. It is further contemplated that the present invention can beused to enhance survivability of and/or to prevent or reduce damage tobiological matter, which may be subject to or under adverse conditions.

In particular embodiments, methods of the present invention are used toinduce stasis or pre-stasis in biological matter, e.g., cells, tissues,organs, and/or organisms, after an injury (e.g., a traumatic injury) orafter the onset or progression of a disease, in order to protect thebiological matter from damage associated with the injury or diseaseprior to, during, or following treatment of the injury or disease. Inother embodiments, methods of the present invention are used to induceor promote stasis or pre-stasis in biological matter prior to subjectionto an injurious event (e.g., an elective surgery) or prior to the onsetor progression of a disease, in order to protect the biological matterfrom damage associated with adverse conditions such as injury ordisease. Such methods are generally referred to as “pre-treatment” withan active compound. Pre-treatment includes methods wherein biologicalmatter is provided with an active compound both before and during, andbefore, during and after biological matter is subjected to adverseconditions (e.g., an injury or onset or the progression of a disease),and methods wherein biological matter is provided with an activecompound only before biological matter is subjected to adverseconditions.

According to various embodiments of the methods of the presentinvention, stasis may be induced by treating biological matter with anactive compound that induces stasis directly itself or, alternatively,by treating biological matter with an active compound that does notitself induce stasis, but instead, promotes or enhances the ability ofor decreases the time required for the biological matter to achievestasis in response to another stimuli, such as, but not limited to, aninjury, a disease, hypoxia, excessive bleeding, or treatment withanother active compound.

In particular embodiments, treatment with an active compound induces“pre-stasis,” which refers to a hypometabolic state through whichbiological matter must transition to reach stasis. Pre-stasis ischaracterized by a reduction in metabolism within the biologicalmaterial of a magnitude that is less than that defined as stasis. Inorder to achieve stasis using an active compound, the biological matternecessarily must transition through a graded hypometabolic state inwhich oxygen consumption and CO₂ production are reduced less thantwo-fold in the biological matter. Such a continuum, in which metabolismor cellular respiration is reduced by an active compound to a degreeless than two-fold, can be described as a state of “pre-stasis”.

To the extent that stasis comprises a two-fold reduction (i.e., areduction to 50% or less) in either CO₂ production or O₂ consumption,direct measurement of these parameters in the biological matter usingmethods known to those in the art in which a reduction of less thantwo-fold is detected is indicative of pre-stasis. Accordingly, certainmeasurements of carbon dioxide and oxygen levels in the blood as well asother markers of metabolic rate familiar to those skilled in the artincluding, but not limited to, blood PO₂, VO₂, pCO₂, pH, and lactatelevels, may be used in the instant invention to monitor the onset orprogression of pre-stasis. While indicators of metabolic activity, e.g.,CO₂ production via cellular respiration and O₂ consumption, are reducedless than two-fold as compared to normal conditions, pre-stasis may beassociated with an at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or50% reduction in CO₂ evolution, which refers to the amount of CO₂released from the lungs. In addition, in various embodiments, pre-stasisis characterized by a reduction in one or more indicators of metabolicactivity that is less than or equal to 1%, 2%, 5%, 10%, 15%, 20%, 25%,30%, 35%, 40%, 45%, or 49% as compared to normal physiologicalconditions. In other embodiments, pre-stasis is characterized by itsability to enhance or promote entry into stasis in response to anotherstimuli (wherein the another stimuli may include prolonged treatmentwith the same active agent), or its ability to enhance survival of orprotect biological matter from damage resulting from an injury, theonset or progression of the disease, or bleeding, particularly bleedingthat can lead to irreversible tissue damage, hemorrhagic shock, orlethality.

While methods of the present invention explicitly exemplified herein mayrefer to inducing “stasis,” it is understood that these methods may bereadily adapted to induce “pre-stasis,” and that such methods ofinducing pre-stasis are contemplated by the present invention. Inaddition, the same active compounds used to induce stasis may also beused to induce pre-stasis, by providing them to biological matter at alower dosage and/or for a shorter time than used to induce stasis.

In certain embodiments, the present invention involves exposingbiological matter to an amount of an agent, so as to achieve stasis ofthe biological matter. In some embodiments, the present inventionconcerns methods for inducing stasis in in vivo biological mattercomprising: a) identifying an organism in which stasis is desired; and,b) exposing the organism to an effective amount of an oxygen antagonistor other active compound to induce stasis in the in vivo biologicalmatter. Inducing “stasis” in biological matter means that the matter isalive but is characterized by one or more of the following: at least atwo-fold reduction in the rate or amount of carbon dioxide production bythe biological matter; at least a two-fold (i.e., 50%) reduction in therate or amount of oxygen consumption by the biological matter; and atleast a 10% decrease in movement or motility (applies only to cells ortissue that move, such as sperm cells or a heart or a limb, or whenstasis is induced in the entire organism) (collectively referred to as“cellular respiration indicators”). In certain embodiments of theinvention, it is contemplated that there is about, at least about, or atmost about a 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 15-, 20-, 25-, 30-,35-, 40-, 45-, 50-, 60-, 70-, 80-, 90-, 100-, 150-, 200-, 250-, 300-,350-, 400-, 450-, 500-, 600-, 700-, 800-, 900-, 1000-, 1100-, 1200-,1300-, 1400-, 1500-, 1600-, 1700-, 1800-, 1900-, 2000-, 2100-, 2200-,2300-, 2400-, 2500-, 2600-, 2700-, 2800-, 2900-, 3000-, 3100-, 3200-,3300, 3400-, 3500-, 3600-, 3700-, 3800-, 3900-, 4000-, 4100-, 4200-,4300-, 4400-, 4500-, 5000-, 6000-, 7000-, 8000-, 9000-, or 10000-fold ormore reduction in the rate of oxygen consumption by the biologicalmatter, or any range derivable therein. Alternatively, it iscontemplated that embodiments of the invention may be discussed in termsof a reduction in the rate of oxygen consumption by the biologicalmatter as about, at least about, or at most about 50, 51, 52, 53, 54,55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,91, 92, 93, 94, 95, 96, 97, 98, 99% or more, or any range derivabletherein. It is contemplated that any assay to measure oxygen consumptionmay be employed, and a typical assay will involve utilizing a closedenvironment and measuring the difference between the oxygen put into theenvironment and oxygen that is left in the environment after a period oftime. It is further contemplated that carbon dioxide production can bemeasured to determine the amount of oxygen consumption by biologicalmatter. Thus, there may be decreases in carbon dioxide production, whichwould correspond to the decreases in oxygen consumption discussed above.

In methods of the invention, stasis or pre-stasis is temporary and/orreversible, meaning that the biological matter no longer exhibits thecharacteristics of stasis at some later point in time. In someembodiments of the invention, instead of an oxygen antagonist, acompound that is not does not qualify as an oxygen antagonist isadministered. It is contemplated that methods discussed with respect tooxygen antagonists may be applied with respect to any compound that isan oxygen antagonist, protective metabolic agent, compound with thestructure of Formula I, II, III, or IV, any other compound discussedherein, or a salt or precursor thereof. A compound that achieves anymethod of the invention and qualifies as an oxygen antagonist,protective metabolic agent, compound with the structure of Formula I,II, III, or IV, or a salt or precursor thereof, will be considered an“active compound.” In particular embodiments, induction of stasis isdesired in which case the compound may be referred to as an “activestasis compound.” It is contemplated that in some embodiments of theinvention, a method is achieved by inducing stasis. For example,therapeutic methods may involve inducing stasis, in which case theactive compound is an active stasis compound. It is specificallycontemplated that in embodiments in which active compounds arediscussed, the invention includes, and may be limited to, oxygenantagonists.

In certain embodiments of the present invention, biological matter istreated with an active compound that does not induce stasis by itself(at least not at the level and/or duration of time provided), but ratherinduces biological matter to enter a pre-stasis state that hastherapeutic benefits and that enhances the ability of the biologicalmatter to achieve stasis in response to another stimuli, such as, e.g.,an injury, disease state, or treatment with another active compound orthe same active compound If used for a longer duration or greaterdosage.

The term “biological matter” refers to any living biological material(mammalian biological material in preferred embodiments) includingcells, tissues, organs, and/or organisms, and any combination thereof.It is contemplated that stasis may be induced in a part of an organism(such as in cells, in tissue, and/or in one or more organs), whetherthat part remains within the organism or is removed from the organism,or the whole organism will be placed in a state of stasis. Moreover, itis contemplated in the context of cells and tissues that homogenous andheterogeneous cell populations may be the subject of embodiments of theinvention. The term “in vivo biological matter” refers to biologicalmatter that is in vivo, i.e., still within or attached to an organism.Moreover, the term “biological matter” will be understood as synonymouswith the term “biological material.” In certain embodiments, it iscontemplated that one or more cells, tissues, or organs is separate froman organism. The term “isolated” can be used to describe such biologicalmatter. It is contemplated that stasis may be induced in isolatedbiological matter.

An organism or other biological matter in need of stasis is an organismor biological matter in which stasis of all or part of the organism mayyield direct or indirect physiological benefits. For example, a patientat risk for hemorrhagic shock may be considered in need of stasis, or apatient who will undergo coronary artery bypass surgery may benefit fromprotecting the heart from ischemia/reperfusion injury. Otherapplications are discussed throughout the application. In some cases, anorganism or other biological matter is identified or determined to be inneed of stasis based on one or more tests, screens, or evaluations thatindicate a condition or disease, or the risk of a condition or diseasethat can be prevented or treated by undergoing stasis. Alternatively,the taking of a patient medical or family medical history (patientinterview) may yield information that an organism or other biologicalmatter is in need of stasis. As would be evident to one skilled in theart, one application of the present invention would be to reduce theoverall energy demands of a biological material by inducing stasis.

Alternatively, an organism or other biological matter may be in need ofan active compound to enhance survivability. For instance, a patient mayneed treatment for an injury or disease or any other applicationdiscussed herein. They may be determined to be in need of enhancedsurvivability or treatment based on methods discussed in the previousparagraph, such as by taking a patient medical or family medicalhistory.

The term “oxygen antagonist” refers to a substance that competes withoxygen insofar as it is used by a biological matter that requires oxygenfor it to be alive (“oxygen-utilizing biological matter”). Oxygen istypically used or needed for various cellular processes that create thebiological matter's primary source of readily utilizable energy. Anoxygen antagonist effectively reduces or eliminates the amount of oxygenthat is available to the oxygen-utilizing biological matter, and/or theamount of oxygen that can be used by the oxygen-utilizing biologicalmatter. In one embodiment, an oxygen antagonist may achieve its oxygenantagonism directly. In another embodiment, an oxygen antagonist mayachieve its oxygen antagonism indirectly.

A direct oxygen antagonist competes with molecular oxygen for thebinding to a molecule (e.g., a protein) that has an oxygen binding siteor oxygen binding capacity. Antagonism may be competitive,non-competitive, or uncompetitive as known in the art of pharmacology orbiochemistry. Examples of direct oxygen antagonists include, but are notlimited to, carbon monoxide (CO), which competes for oxygen binding tohemoglobin and to cytochrome c oxidase.

An indirect oxygen antagonist influences the availability or delivery ofoxygen to cells that use oxygen for energy production (e.g., in cellularrespiration) in the absence of directly competing for the binding ofoxygen to an oxygen-binding molecule. Examples of indirect oxygenantagonists include, but are not limited to, (i) carbon dioxide, which,through a process known as the Bohr effect, reduces the capacity ofhemoglobin (or other globins, like myoglobin) to bind to oxygen in theblood or hemolymph of oxygen-utilizing animals, thereby reducing theamount of oxygen that is delivered to oxygen-utilizing cells, tissues,and organs of the organism, thereby reducing the availability of oxygento cells that use oxygen; (ii) inhibitors of carbonic anhydrase (Supuranet al., 2003, incorporated by reference in its entirety) which, byvirtue of inhibiting the hydration of carbon dioxide in the lungs orother respiratory organs, increase the concentration of carbon dioxide,thereby reducing the capacity of hemoglobin (or other globins, likemyoglobin) to bind to oxygen in the blood or hemolymph ofoxygen-utilizing animals, thereby reducing the amount of oxygen that isdelivered to oxygen-utilizing cells, tissues, and organs of theorganism, thereby reducing the availability of oxygen to cells that useoxygen; and, (iii) molecules that bind to oxygen and sequester it fromor rendering it unavailable to bind to oxygen-binding molecules,including, but not limited to oxygen chelators, antibodies, and thelike.

In some embodiments, an oxygen antagonist is both a direct and anindirect oxygen antagonist. Examples include, but are not limited to,compounds, drugs, or agents that directly compete for oxygen binding tocytochrome c oxidase and are also capable of binding to and inhibitingthe enzymatic activity of carbonic anhydrase. Thus, in some embodimentsan oxygen antagonist inhibits or reduces the amount of cellularrespiration occurring in the cells, for instance, by binding sites oncytochrome c oxidase that would otherwise bind to oxygen. Cytochrome coxidase specifically binds oxygen and then converts it to water. In someembodiments, such binding to cytochrome c oxidase is preferablyreleasable and reversible binding (e.g., has an in vitro dissociationconstant, K_(d), of at least 10⁻², 10⁻³, or 10⁻⁴ M, and has an in vitrodissociation constant, K_(d), not greater than 10⁻⁶, 10⁻⁷, 10⁻⁸, 10⁻⁹,10⁻¹⁰, or 10⁻¹¹ M). In some embodiments, an oxygen antagonist isevaluated by measuring ATP and/or carbon dioxide output.

The term “effective amount” means an amount that can achieve the statedresult. In certain methods of the invention, an “effective amount” is,for example, an amount that induces stasis in the biological matter inneed of stasis. In other methods, an “effective amount” is, for example,an amount that induces pre-stasis in biological matter in need of stasisor in need of enhanced survival. In additional embodiments, an“effective amount” may refer to an amount that increases thesurvivability of an organism or other biological matter. This can bedetermined (or assumed) based on comparison or previous comparison tountreated biological matter or biological matter treated with adifferent dosage or regimen that does not experience a difference insurvivability.

It will be understood that when inducing stasis in a tissue or organ, aneffective amount is one that induces stasis in the tissue or organ asdetermined by the collective amount of cellular respiration of thetissue or organ. Accordingly, for example, if the level of oxygenconsumption by a heart (collectively with respect to cells of the heart)is decreased at least about 2-fold (i.e., 50%) after exposure to aparticular amount of a certain oxygen antagonist or other active stasiscompound, it will be understood that that was an effective amount toinduce stasis in the heart. Similarly, an effective amount of an agentthat induces stasis in an organism is one that is evaluated with respectto the collective or aggregate level of a particular parameter ofstasis. It will be also understood that when inducing stasis in anorganism, an effective amount is one that induces stasis generally ofthe whole organism, unless a particular part of the organism wastargeted. In addition, it is understood that an effective amount may bean amount sufficient to induce stasis by itself, or it may be an amountsufficient to induce stasis in combination with another agent orstimuli, e.g., another active compound, an injury, or a disease state.

The concept of an effective amount of a particular compound is related,in some embodiments, to how much utilizable oxygen there is available tothe biological matter. Generally, stasis can be induced when there isabout 100,000 ppm or less of oxygen in the absence of any oxygenantagonist (room air has about 210,000 ppm oxygen). The oxygenantagonist serves to alter how much oxygen is effectively available. Atconcentration of 10 ppm of oxygen, suspended animation is induced. Thus,while the actual concentration of oxygen that biological matter isexposed to may be higher, even much higher, than 10 ppm, stasis can beinduced because of the competitive effect of an oxygen antagonist withoxygen for binding to essential oxygen metabolizing proteins in thebiological matter. In other words, an effective amount of an oxygenantagonist reduces the effective oxygen concentration to a point wherethe oxygen that is present cannot be used. This will happen when theamount of an oxygen antagonist reduces the effective oxygenconcentration below the K_(m) of oxygen binding to essential oxygenmetabolizing proteins (i.e., comparable to 10 ppm of oxygen).Accordingly, in some embodiments, an oxygen antagonist reduces theeffective concentration of oxygen by about or at least about 2-, 3-, 4-,5-, 6-, 7-, 8-, 9-, 10-, 15-, 20-, 25-, 30-, 35-, 40-, 45-, 50-, 60-,70-, 80-, 90-, 100-, 150-, 200-, 250-, 300-, 350-, 400-, 450-, 500-,600-, 700-, 800-, 900-, 1000-, 1100-, 1200-, 1300-, 1400-, 1500-, 1600-,1700-, 1800-, 1900-, 2000-, 2100-2200-, 2300-, 2400-, 2500-, 2600-,2700-, 2800-, 2900-, 3000-, 3100-, 3200-, 3300, 3400-, 3500-, 3600-,3700-, 3800-, 3900-, 4000-, 4100-, 4200-, 4300-, 4400-, 4500-, 5000-,6000-, 7000-, 8000-, 9000-, or 10000-fold or more, or any rangederivable therein. Alternatively, it is contemplated that embodiments ofthe invention may be discussed in terms of a reduction in effectiveoxygen concentration as about, at least about, or at most about 50, 51,52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99% or more, or any rangederivable therein. It is understood that this is another way ofindicating a decrease in cellular respiration.

Furthermore, in some embodiments, stasis can be measured indirectly by adrop in core body temperature of an organism. It is contemplated that areduction in core body temperature of about, at least about, or at mostabout 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50° F. or more, or any rangederivable therein may be observed in methods of the invention. In someembodiments of the invention, hypothermia can be induced, such asmoderate hypothermia (at least 10° F. reduction) or severe hypothermia(at least 20° F. reduction).

Moreover, the effective amount can be expressed as a concentration withor without a qualification on length of time of exposure. In someembodiments, it is generally contemplated that to induce stasis orachieve other stated goals of the invention, the biological matter isexposed to an oxygen antagonist or other active compound for about, atleast about, or at most about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,60 seconds, 1,2,3,4,5,6,7,8,9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2, 3, 4, 5, 6, 7days, 1, 2, 3, 4, 5 weeks, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 months,1,2,3,4,5,6,7,8,9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or moreyears, and any combination or range derivable therein. It is furthercontemplated that the amount of time may be indefinite, depending on thereason or purpose for administering the oxygen antagonist or otheractive compound. Thereafter, biological matter may continue to beexposed to an oxygen antagonist or other active compound, or, in otherembodiments of the invention, the biological matter may no longer beexposed to the oxygen antagonist or other active compound. This latterstep can be achieved either by removing or effectively removing theoxygen antagonist or other active compound from the presence of thebiological matter in which stasis was desired, or the biological mattermay be removed from an environment containing the oxygen antagonist orother active compound. Additionally, matter may be exposed to orprovided with any active compound continuously (a period of time withouta break in exposure), intermittently (exposure on multiple occasions),or on a periodic basis (exposure on multiple occasions on a regularbasis). The dosages of the active compound on these different bases maythe same or they may vary. In certain embodiments, an active compound isprovided periodically by providing or exposing biological matter to anactive compound 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 times every 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41,42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,60 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24 hours, 1,2,3,4,5,6,7 days, 1,2,3,4,5 weeks,1,2,3,4,5,6,7,8,9,10, 11, 12 months, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,12, 13, 14, 15, 16, 17, 18, 19, 20 or more years, or any range derivabletherein.

Furthermore, in some embodiments of the invention, biological matter isexposed to or provided with an active compound for a sustained period oftime, where “sustained” means a period of time of at least about 2hours. In other embodiments, biological matter may be exposed to orprovided with an active compound on a sustained basis for more than asingle day. In such circumstances, the biological matter is providedwith an active compound on a continuously sustained basis. In certainembodiments, biological matter may be exposed to or provided with anactive compound for about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or morehours (or any range derivable therein) for 2, 3, 4, 5, 6, 7 days, and/or1, 2, 3, 4, 5 weeks, and/or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12months, and/or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20 or more years (or any range derivable therein)continuously, intermittently (exposure on multiple occasions), or on aperiodic basis (exposure on a recurring regular basis).

In some embodiments, biological matter may be exposed to or providedwith an active compound at least before and during; before, during, andafter; during and after; or solely after a particular injury, trauma, ortreatment (for instance, surgery), adverse condition or other relevantevent or situation. This exposure may or may not be sustained.

The dosages of the active compound on these different bases may the sameor they may vary.

Moreover, in certain embodiments, an active compound may be provided ona continuously sustained basis at level that is considered “low,”meaning a level that is less than the amount that causes metabolicflexibility such as seen with drop in CBT, heart rate, or CO₂ or O₂consumption or production.

In certain embodiments, biological matter is exposed or provided anactive compound, such as a metabolic agent, in an amount that exceedswhat was previously understood to be the maximum tolerated dose beforeadverse physiological ramifications such as apnea (“period of timeduring which breathing is markedly reduced such that the subject takes10% or fewer number of breaths”), lack of observable skeletal musclemovement, dystonia, and/or hyperactivity. Such an amount may beparticularly relevant to increasing survivability in some embodiments ofthe invention, for instance, to increase the chances of survivingadverse conditions, such as those that would induce death fromhemorrhagic shock.

A physiological state can be induced by active compounds of the presentinvention which enhances survivability in an organism in need ofsurvivability enhancement and comprises a set of observablephysiological changes in response to an effective dose of an activecompound, said changes may comprise one, more or all of hyperpnea, apneaand the concomitant or subsequent loss of neuromuscular tone orvoluntary control of movement with continued heartbeat. A transient andmeasurable change in arterial blood color may also be observed.Hyperpnea refers to rapid, shallow breathing. Apnea refers to acessation of breathing or the reduction as described above.

In certain embodiments, the subject becomes apneic, which is marked by acessation in breathing and then an apnic breath after a short period oftime. In rats, this occurs after approximately 20 seconds. Thus, it iscontemplated that a subject induced into apnea may exhibit 0, 1, 2, 3,4, 5, 6, 7, 8, 9, 10% the number of breaths subsequent to exposure to anactive compound. The subject may have an occasional breath, which may beconsidered an apnic breath, thereafter. In certain embodiments of theinvention, apnea continues until the subject is no longer exposed to theactive compound.

In some embodiments of the invention, an effective amount may beexpressed as LD₅₀, which refers to the “median lethal dose,” which meansthe dose that is administered that kills half the population of animals(causes 50% mortality). Moreover, in further embodiments, an effectiveamount may be independent of the weight of the biological matter(“weight independent”). In rodents and humans, for example, the LD₅₀ ofH₂S gas is approximately 700 ppm before adverse physiological effectsoccur. Moreover, in some embodiments of the invention, increasingsurvivability refers generally to living longer, which is an embodimentof the invention.

The present invention also concerns methods for inducing apnea in anorganism comprising administering to the organism an effective amount ofan active compound. In certain embodiments, the organism also does notexhibit any skeletal muscle movement as a result of the active compound.It is specifically contemplated that the organism may be mammal,including a human. In other embodiments, an effective amount exceedswhat is considered a lethal concentration. In further embodiments, theconcentration may be a lethal amount though the exposure time may beabout, at least about, or at most about 10, 15, 20, 25, 30, 35, 40, 45,50, 55, 60 seconds, 1, 2, 3, 4, 5 minutes or more (or any rangederivable therein or any other time period specified in thisdisclosure). In particular embodiments, a mammal is exposed to at leastabout 600 ppm of an active gas compound, such as H₂S.

Additionally, in certain embodiments, there is a step of identifying ananimal in need of treatment. In other embodiments, there is a step ofobserving apnea in the organism. In even further embodiments, methodsinvolving obtaining a blood sample from the organism and/or evaluatingthe color of the organism's blood. It has been observed that exposure toH₂S changes the color of blood from a mammal; it goes from bright red toa darker, red wine color and then to brick red. Evaluating the color maybe done visually without any instruments or machines, while in otherembodiments, an instrument may be used, such as a spectrophotometer.Furthermore, a blood sample may be obtained from an organism and othertypes of analysis may be done on it. Alternatively, a blood sample maynot be needed and instead, blood may be evaluated without the sample.For instance, a modified pulse-oximeter that shines IR or visible lightthrough the finger may be employed to monitor color changes in theblood.

In certain embodiments, biological matter is exposed to an effectiveamount of an active compound that does not lead to stasis or pre-stasis.In some embodiments, there may be no evidence of a reduction in oxygenconsumption or carbon dioxide production while the active compound ispresent.

In additional embodiments, an organism may be exposed to the activecompound while sleeping. Moreover, as discussed above, the exposure maybe regular, such as daily (meaning exposure at least once a day).

It is specifically contemplated that in some embodiments an activecompound is provided to a subject by nebulizer. This may be applied withany embodiment of the invention. In certain cases, the nebulizer is usedfor the treatment of hemorrhagic shock. In further embodiments, theactive compound is provided as a single dose to the subject. In specificcases, a single dose or multiple doses is one that would induce apnea ina subject. In some embodiments, a subject is given at least about 1,000,2,000, 3,000, 4,000, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 11,000,12,000 or more ppm H₂S gas. The exposure time may be any of the timesdiscussed herein, including about or about at most 10, 9, 8, 7, 6, 5, 4,3, 2, 1, 0.5, 0.1 minutes or less (or any range derivable therein).

In further embodiments, after exposure to an active compound themetabolic rate of biologic matter may change. In certain embodiments,the RQ ratio (CO₂ production/O₂ consumption) of the biological matterchanges after exposure to an active compound. This may occur after aninitial exposure or repeated exposure or after an acute exposure. Insome embodiments, the RQ ratio decreases after exposure. The decreasemay be a decrease of about, at least about or at most about 5, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80% or more, or anyrange derivable therein. The decrease may be a result of O₂ consumptionincreasing of CO₂ production decreasing in relation to O₂ consumption.

In some embodiments, no other physiological change is observed inbiological matter exposed to the active compound except that its RQratio changes after the exposure. Therefore, in some embodiments of theinvention, methods involve measuring an RQ ratio in a subject. This mayoccur before and/or after exposure to the active compound.

Therefore, in some embodiments of the invention, stasis is induced, anda further step in methods of the invention is to maintain the relevantbiological matter in a state of stasis. This can be accomplished bycontinuing to expose the biological matter to an oxygen antagonist orother active compound and/or exposing the biological matter to anonphysiological temperature or another oxygen antagonist or otheractive compound. Alternatively, the biological matter may be placed in apreservation agent or solution, or be exposed to normoxic or hypoxicconditions. It is contemplated that biological matter may be maintainedin stasis for about, at least about, or at most about 30 seconds, 1, 2,3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 minutes, 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24hours, 1, 2, 3, 4, 5, 6, 7 days, 1, 2, 3, 4, 5 weeks,1,2,3,4,5,6,7,8,9,10, 11, 12 months, 1,2,3,4,5,6,7,8,9,10, 11, 12, 13,14, 15, 16, 17, 18, 19, 20 or more years, and any combination or rangederivable therein. Moreover, it is contemplated that in addition to orinstead of changing the temperature, other changes in the environmentmay be implemented such as a change in pressure or to effect acryoprotectant or cryopreservation environment (e.g., one containingglycerol).

It will be appreciated that “stasis” with respect to a whole animal and“stasis” with respect to cells or tissues may require different lengthsof time in stasis. Thus, with respect to human subjects, e.g., subjectsundergoing a surgical treatment, treatment for malignant hyperthermia,or trauma victim, a time of stasis of up to 12, 18, or 24 hours isgenerally contemplated. With respect to non-human animal subjects, e.g.non-human animals shipped or stored for commercial purposes, stasis fora period of 2 or 4 days, 2 or 4 weeks, or longer is contemplated.

The term “expose” is used according to its ordinary meaning to indicatethat biological matter is subjected to an oxygen antagonist or otheractive compound. This can be achieved in some embodiments by contactingbiological matter with an oxygen antagonist or active compound. In otherembodiments, this is achieved by contacting the biological matter withan active compound, which may or may not be an oxygen antagonist. In thecase of in vivo cells, tissues, or organs, “expose” may further mean “tolay open” these materials so that it can be contacted with an oxygenantagonist or other active compound. This can be done, for example,surgically. Exposing biological matter to an oxygen antagonist or otheractive compound can be by incubation in or with (includes immersion) theantagonist, perfusion or infusion with the antagonist, injection ofbiological matter with an oxygen antagonist or other active compound, orapplying an oxygen antagonist or other active compound to the biologicalmatter. In addition, if stasis of the entire organism is desirable,inhalation or ingestion of the oxygen antagonist or other activecompound, or any other route of pharmaceutical administration iscontemplated for use with oxygen antagonists or other active compound.Furthermore, the term “provide” is used according to its ordinary andplain meaning to mean “to supply.” It is contemplated that a compoundmay be provided to biological matter in one form and be converted bychemical reaction to its form as an active compound. The term “provide”encompasses the term “expose” in the context of the term “effectiveamount,” according to the present invention.

In some embodiments, an effective amount is characterized as a sublethaldose of the oxygen antagonist or other active compound. In the contextof inducing stasis of cells, tissues, or organs (not the wholeorganism), a “sublethal dose” means a single administration of theoxygen antagonist or active compound that is less than half of theamount of the oxygen antagonist or active compound that would cause atleast a majority of cells in a biological matter to die within 24 hoursof the administration. If stasis of the entire organism is desired, thena “sublethal dose” means a single administration of the oxygenantagonist or active compound that is less than half of the amount ofthe oxygen antagonist that would cause the organism to die within 24hours of the administration. In other embodiments, an effective amountis characterized as a near-lethal dose of the oxygen antagonist oractive compound. Similarly, in the context of inducing stasis of cells,tissues, or organs (not the whole organism), a “near lethal dose” meansa single administration of the oxygen antagonist or active compound thatis within 25% of the amount of the inhibitor that would cause at least amajority of cell(s) to die within 24 hours of the administration. Ifstasis of the entire organism is desired, then a “near lethal dose”means a single administration of the oxygen antagonist or activecompound that is within 25% of the amount of the inhibitor that wouldcause the organism to die within 24 hours of the administration. In someembodiments a sublethal dose is administered by administering apredetermined amount of the oxygen antagonist or active compound to thebiological material. It is specifically contemplated that this may beimplemented with respect to any active compound.

Furthermore, it is contemplated that in some embodiments an effectiveamount is characterized as a supralethal dose of the oxygen antagonistor other active compound. In the context of inducing stasis of cells,tissues, or organs (not the whole organism), a “supra-lethal dose” meansa single administration of an active compound that is at least 1.5 times(1.5×) the amount of the active compound that would cause at least amajority of cells in a biological matter to die within 24 hours of theadministration. If stasis of the entire organism is desired, then a“supra-lethal dose” means a single administration of the active compoundthat is at least 1.5 times the amount of the active compound that wouldcause the organism to die within 24 hours of the administration. It isspecifically contemplated that the supra-lethal dose can be about, atleast about, or at most about 1.5×, 2×, 3×, 4×, 5×, 10×, 20×, 30×, 40×,50×, 60×, 70×, 80×, 90×, 100×, 150×, 200×, 250×, 300×, 400×, 500×, 600×,700×, 800×, 900×, 1000×, 1100×, 1200×, 1300×, 1400×, 1500×, 1600×,1700×, 1800×, 1900×, 2000×, 3000×, 4000×, 5000×, 6000×, 7000×, 8000×,9000×, 10,000× or more, or any range derivable therein, the amount ofthe active compound that would cause at least a majority of cells in abiological matter (or the entire organism) to die within 24 hours of theadministration.

The amount of the active compound that is provided to biological mattercan be about, at least about, or at most about 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98,99, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220,230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360,370, 380, 390, 400, 410, 420, 430, 440, 441, 450, 460, 470, 480, 490,500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630,640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770,780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910,920, 930, 940, 950, 960, 970, 980, 990, 1000 mg, mg/kg, or mg/m2, or anyrange derivable therein. Alternatively, the amount may be expressed as1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56,57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74,75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92,93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150, 160, 170, 180,190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320,330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 441, 450,460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590,600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730,740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870,880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, 1000 mM orM, or any range derivable therein.

In some embodiments an effective amount is administered by monitoring,alone or in combination, the amount of oxygen antagonist or other activecompound administered, monitoring the duration of administration of theoxygen antagonist or other active compound, monitoring a physiologicalresponse (e.g., pulse, respiration, pain response, movement or motility,metabolic parameters such as cellular energy production or redox state,etc.) of the biological material to the administration of the oxygenantagonist or other active compound and reducing, interrupting orceasing administration of the compound(s) when a predetermined floor orceiling for a change in that response is measured, etc. Moreover, thesesteps can be employed additionally in any method of the invention.

Tissue in a state of stasis or that has undergone stasis can be used ina number of applications. They can be used, for example, for transfusionor transplantation (therapeutic applications, including organtransplants); for research purposes; for screening assays to identify,characterize, or manufacture other compounds that induce stasis; fortesting a sample from which the tissue was obtained (diagnosticapplications); for preserving or preventing damage to the tissue thatwill be placed back into the organism from which they were derived(preventative applications); and for preserving or preventing damage tothem during transport or storage. Details of such applications and otheruses are described below. The term “isolated tissue” means that thetissue is not located within an organism. In some embodiments, thetissue is all or part of an organ. The terms “tissue” and “organ” areused according to their ordinary and plain meanings. Though tissue iscomposed of cells, it will be understood that the term “tissue” refersto an aggregate of similar cells forming a definite kind of structuralmaterial. Moreover, an organ is a particular type of tissue.

The present invention concerns methods for inducing stasis in isolatedtissue comprising: a) identifying the tissue in which stasis is desired;and, b) exposing the tissue to an effective amount of an oxygenantagonist to induce stasis.

Compositions, methods, and articles of manufacture of the invention canbe used on biological matter that will be transferred back into thedonor organism from which it was derived (autologous) or a differentrecipient (heterologous) subject. In some embodiments, biological matteris obtained directly from a donor organism. In others, the biologicalmatter is placed in culture prior to exposure to an oxygen antagonist orother active compound. In some situations, the biological matter isobtained from a donor organism administered extracorporeal membraneoxygenation prior to retrieval of the biological matter, which is atechnique implemented to aid in the preservation of biological matter.Moreover, methods include administering or implanting the biologicalmatter in which stasis was induced to a live recipient organism.

In some embodiments, an organ or tissue to be retrieved and thentransplanted is exposed to the oxygen antagonist or other activecompound while still in the donor subject. It is contemplated that insome cases, the vasculature of the donor is used to expose the organ ortissue to the oxygen antagonist or other active compound. This can bedone if the heart is still pumping or a pump, catheter, or syringe canbe used to administer the oxygen antagonist or other active compoundinto the vasculature for delivery to the organ or tissue

Methods of the invention also concern inducing stasis in isolated tissuecomprising incubating the tissue with an oxygen antagonist or activestasis compound that creates hypoxic conditions for an effective amountof time for the tissue to enter stasis.

Cells in a state of stasis or that have undergone stasis can be used ina number of applications. They can be used, for example, for transfusionor transplantation (therapeutic applications); for research purposes;for screening assays to identify, characterize, or manufacture othercompounds that induce stasis; for testing a sample from which the cellswere obtained (diagnostic applications); for preserving or preventingdamage to the cells that will be placed back into the organism fromwhich they were derived (preventative applications); and for preservingor preventing damage to cells during transport or storage. Details ofsuch applications and other uses are described below.

The present invention concerns methods for inducing stasis in one ormore cells separate from an organism comprising: a) identifying thecell(s) in which stasis is desired; and, b) exposing the cell(s) to aneffective amount of an oxygen antagonist or other active stasis compoundto induce stasis.

It is contemplated that the cell may be any oxygen-utilizing cell. Thecell may be eukaryotic or prokaryotic. In certain embodiments, the cellis eukaryotic. More particularly, in some embodiments, the cell is amammalian cell. Mammalian cells contemplated for use with the inventioninclude, but are not limited to those that are from a: human, monkey,mouse, rat, rabbit, hamster, goat, pig, dog, cat, ferret, cow, sheep,and horse.

Moreover, cells of the invention may be diploid but in some cases, thecells are haploid (sex cells). Additionally, cells may be polyploid,aneuploid, or anucleate. The cell can be from a particular tissue ororgan, such as one from the group consisting of: heart, lung, kidney,liver, bone marrow, pancreas, skin, bone, vein, artery, cornea, blood,small intestine, large intestine, brain, spinal cord, smooth muscle,skeletal muscle, ovary, testis, uterus, and umbilical cord. Moreover,the cell can also be characterized as one of the following cell types:platelet, myelocyte, erythrocyte, lymphocyte, adipocyte, fibroblast,epithelial cell, endothelial cell, smooth muscle cell, skeletal musclecell, endocrine cell, glial cell, neuron, secretory cell, barrierfunction cell, contractile cell, absorptive cell, mucosal cell, limbuscell (from cornea), stem cell (totipotent, pluripotent or multipotent),unfertilized or fertilized oocyte, or sperm.

The present invention also provides methods, compositions, and apparatifor enhancing survivability of and/or reducing damage to biologicalmatter under adverse conditions by reducing metabolic demand, oxygenrequirements, temperature, or any combination thereof in the biologicalmatter of interest. In some embodiments of the invention, survivabilityof biological matter is enhanced by providing it with an effectiveamount of a protective metabolic agent. The agent enhances survivabilityby preventing or reducing damage to the biological matter, preventingall or part of the matter from dying or senescing, and/or extending thelifespan of all or part of the biological matter, relative to biologicalmatter not exposed to the agent. Alternatively, in some embodiments theagent prolongs survival of tissue and/or an organism that wouldotherwise not survive without the agent.

It is contemplated that a “protective metabolic agent” is a substance orcompound capable of reversibly altering the metabolism of biologicalmatter that is exposed to or contacted with it and that promotes orenhances the survivability of the biological matter.

In certain embodiments, the protective metabolic agent induces stasis inthe treated biological matter; while, in other embodiments, theprotective metabolic agent does not directly itself induce stasis in thetreated biological matter. Protective metabolic agents, and other activecompounds, may enhance survivability and/or reduce damage to biologicalmatter without inducing stasis in the biological matter per se, butrather by reducing cellular respiration and corresponding metabolicactivity to a degree that is less than about a fifty percent decrease inoxygen consumption or carbon dioxide production. Additionally, suchcompounds may cause the biological matter to more quickly, easily, oreffectively enter into or achieve stasis in response to an injury ordisease state, e.g., by inducing the biological matter to achieve astate of pre-stasis.

Survivability includes survivability when the matter is under adverseconditions—that is, conditions under which there can be adverse andnonreversible damage or injury to biological matter. Adverse conditionscan include, but are not limited to, when oxygen concentrations arereduced in the environment (hypoxia or anoxia, such as at high altitudesor under water); when the biological matter is incapable of receivingthat oxygen (such as during ischemia), which can be caused by i) reducedblood flow to organs (e.g., heart, brain, and/or kidneys) as a result ofblood vessel occlusion (e.g., myocardial infarction, and/or stroke), ii)extracorporeal blood shunting as occurs during heart/lung bypass surgery(e.g., “pumphead syndrome” in which heart or brain tissue is damaged asa result of cardiopulmonary bypass), or iii) as a result of blood lossdue to trauma (e.g., hemorrhagic shock or surgery); hypothermia, wherethe biological material is subjected to sub-physiological temperatures,due to exposure to cold environment or a state of low temperature of thebiological material, such that it is unable to maintain adequateoxygenation of the biological materials; hyperthermia, wherebytemperatures where the biological material is subjected tosupra-physiological temperatures, due to exposure to hot environment ora state of high temperature of the biological material such as by amalignant fever; conditions of excess heavy metals, such as irondisorders (genetic as well as environmental) such as hemochromatosis,acquired iron overload, sickle-cell anemia, juvenile hemochromatosisAfrican siderosis, thalassemia, porphyria cutanea tarda, sideroblasticanemia, iron-deficiency anemia and anemia of chronic disease. It iscontemplated that a protective metabolic agent is an oxygen antagonistin certain embodiments of the invention. It is also contemplated that incertain other embodiments, an oxygen antagonist is not a protectivemetabolic agent. In other embodiments of the invention, one or morecompounds may be used to increase or enhance survivability of biologicalmatter; reversibly inhibit the metabolism and/or activity of biologicalmatter; reduce the oxygen requirement of biological matter; reduce orprevent damage to biological matter under adverse conditions; prevent orreduce damage or injury to biological matter; prevent aging orsenescence of biological matter; and, provide a therapeutic benefit asdescribed throughout the application with respect to oxygen antagonists.It is contemplated that embodiments relating to inducing stasis areapplicable to these other embodiments as well. Therefore, any embodimentdiscussed with respect to stasis may be implemented with respect tothese other embodiments.

An active compound used for inducing stasis or any of these otherembodiments may lead or provide their desired effect(s), in someembodiments, only when they are in the context of the biological matter(i.e., have no lasting effect) and/or they may provide for theseeffect(s) for more than 24 hours after the biological matter is nolonger exposed to it. Moreover, this can also be the case when acombination of active compounds is used.

In certain embodiments, biological matter is exposed to an amount of anoxygen antagonist or other active compound that reduces the rate oramount of carbon dioxide production by the biological matter at least2-fold, but also by about, at least about, or at most about 3-, 4-, 5-,6-, 7-, 8-, 9-, 10-, 15-, 20-, 25-, 30-, 35-, 40-, 45-, 50-, 100-, 200-,300-, 400-, 500-fold of more, or any range derivable therein.Alternatively, it is contemplated that embodiments of the invention maybe discussed in terms of a reduction in the rate or amount of carbondioxide production by the biological matter as about, at least about, orat most about 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99%or more, or any range derivable therein. In still further embodiments,biological matter is exposed to an amount of an oxygen antagonist orother active compound that reduces the rate or amount of oxygenconsumption by the biological matter at least 2-fold, but also by about,at least about, or at most about 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 15-,20-, 25-, 30-, 35-, 40-, 45-, 50-, 100-, 200-, 300-, 400-, 500-fold ofmore, or any range derivable therein. Alternatively, it is contemplatedthat embodiments of the invention may be discussed in terms of areduction in the rate or amount of oxygen consumption by the biologicalmatter as about, at least about, or at most about 50, 51, 52, 53, 54,55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,91, 92, 93, 94, 95, 96, 97, 98, 99% or more, or any range derivabletherein. In still further embodiments, biological matter is exposed toan amount of an oxygen antagonist or other active compound thatdecreases movement or motility by at least 10%, but also by about, atleast about, or at most about 15, 20, 25, 30, 35, 40, 45, 50, 55, 60,65, 70, 75, 80, 85, 90, 95, 99, or 100%, or any range derivable therein.As with other embodiments, these characteristics and parameters are inthe context of whichever biological matter is induced into a state ofstasis. Thus, if stasis is induced in an organism's heart, theseparameters would be evaluated for the heart, and not the whole organism.In the context of organisms, a reduction in oxygen consumption on theorder of roughly 8-fold is a kind of stasis referred to as“hibernation.” Moreover, it will be understood in this application thata reduction in oxygen consumption on the order of around 1000-fold canbe considered “suspended animation.” It will be understood thatembodiments of the invention concerning stasis can be achieved at thelevel of hibernation or suspended animation, if appropriate. It isunderstood that a “—fold reduction” is relative to the reduced amount;for example, if a non-hibernating animal consumes 800 units of oxygen,the hibernating animal consumes 100 units of oxygen.

Additionally, in some embodiments of the invention, methods are providedfor reducing cellular respiration, which may or may not be as high asthat needed to reach stasis. A reduction in oxygen consumption by about,at least about, or at most about 1, 2, 5, 10, 15, 20, 25, 30, 35, 40,45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% is provided inmethods of the invention. This can also be expressed and assessed interms of any cellular respiration indicator.

It is contemplated that biological matter may be exposed to one or moreoxygen antagonists or other active compounds more than one time. It iscontemplated that biological matter may be exposed to one or more activecompounds 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more times, meaning when abiological matter is exposed multiple times that there are periods ofrespite (with respect to exposure to the active compound) in between.

It is also contemplated that an active compound may be administeredbefore, during, after, or any combination thereof, in relation to theonset or progression of an injurious insult or disease condition. Incertain embodiments, pre-treatment of biological matter to an activecompound is sufficient to enhance survivability and/or reduce damagefrom an injurious or disease insult. Pre-treatment is defined asexposure of the biological matter to the active compound before theonset or detection of the injurious or disease insult. Pre-treatment canbe followed by termination of exposure at or near the onset of theinsult or continued exposure after the onset of insult.

In certain embodiments, methods including pre-exposure to an activecompound (i.e., pre-treatment) are used to treat conditions in which aninjurious or disease insult is 1) scheduled or elected in advance, or 2)predicted in advance to likely occur. Examples meeting condition 1include, but are not limited to, major surgery where blood loss mayoccur spontaneously or as a result of a procedure, cardiopulmonarybypass in which oxygenation of the blood may be compromised or in whichvascular delivery of blood may be reduced (as in the setting of coronaryartery bypass graft (CABG) surgery), or in the treatment of organ donorsprior to removal of donor organs for transport and transplantation intoa recipient in need of an organ transplant. Examples meeting condition 2include, but are not limited to, medical conditions in which a risk ofinjury or disease progression is inherent (e.g., in the context ofunstable angina, following angioplasty, bleeding aneurysms, hemorrhagicstrokes, following major trauma or blood loss), or in which the risk canbe diagnosed using a medical diagnostic test.

Exposure to the active compound may enhance survivability or reducedamage when exposure occurs after the onset or detection of theinjurious or disease insult to achieve a therapeutic effect. Exposure tothe active compound may be brief or extended. The exposure duration maybe only for as long as needed to reach an indicator of stasis activityor pre-stasis (e.g., blood pCO₂, pO₂, pH, lactate, or sulfhemoglobinlevels, or body temperature), or it may be longer. In certainembodiments, exposure occurs following traumatic injury (includingiatrogenic and/or non-iatrogenic injuries) to an organism and is used toinduce stasis or pre-stasis in the entire organism or injured tissuetherein, so as to prevent or minimize damage, e.g., ischemic andreperfusion injury prior to, during, and/or following treatment.

In one embodiment, the present invention includes a method of protectinga mammal from suffering cellular damage from a surgery, comprisingproviding to the mammal an amount of hydrogen sulfide or other activecompound sufficient to induce the mammal to enter pre-stasis prior tothe surgery. The surgery may be elective, planned, or emergency surgery,such as, e.g., cardiopulmonary surgery. The hydrogen sulfide may beadministered by any means available in the art, including, e.g.,intravenously or by inhalation.

In another embodiment, the present invention includes a method ofprotecting a mammal from suffering cellular damage from a disease oradverse medical condition, comprising providing to the mammal an amountof hydrogen sulfide or other active compound sufficient to induce themammal to enter pre-stasis or stasis prior to the onset or progressionof the disease or adverse medical condition. This embodiment may be usedin the context of a variety of different diseases and adverse medicalconditions, including, e.g., unstable angina, post-angioplasty,aneurism, hemorrhagic stroke or shock, trauma, and blood loss.

In specific embodiments, the invention concerns methods of preventing anorganism, such as a mammal, from bleeding to death or sufferingirreversible tissue damage as a result of bleeding by providing to themammal an amount of hydrogen sulfide or other active compound sufficientto prevent the animal from bleeding to death. In certain additionalembodiments, the organism may go into hemorrhagic shock but not die fromexcessive bleeding. The terms “bleeding” and “hemorrhaging” are usedinterchangeably to refer to any discharge of blood from a blood vessel.It includes, but is not limited to, internal and external bleeding,bleeding from an injury (which may be from an internal source, or froman external physical source such as from a gunshot, stabbing, physicaltrauma, etc.).

Moreover, additional embodiments of the invention concern prevention ofdeath or irreversible tissue damage from blood loss or other lack ofoxygenation to cells or tissue, such as from lack of an adequate bloodsupply. This may be the result of, for example, actual blood loss, or itmay be from conditions or diseases that prevent cells or tissue frombeing perfused (e.g., reperfusion injury), that cause blockage of bloodto cells or tissue, that reduce blood pressure locally or overall in anorganism, that reduce the amount of oxygen is carried in the blood, orthat reduces the number of oxygen carrying cells in the blood.Conditions and diseases that may be involved include, but are notlimited to, blood clots and embolisms, cysts, growths, tumors, anemia(including sickle cell anemia), hemophilia, other blood clottingdiseases (e.g., von Willebrand, ITP), and atherosclerosis. Suchconditions and diseases also include those that create essentiallyhypoxic or anoxic conditions for cells or tissue in an organism becauseof an injury, disease, or condition.

In some cases, a sublethal collective dose or a nonlethal collectivedose is administered to the biological matter. As discussed above, withrespect to inducing stasis in biological matter that is not an entireorganism, a “sublethal collective dose” means an amount of multipleadministrations of the active compound that collectively is less thanhalf of the amount of the active compound that would cause at least amajority of cell(s) to die within 24 hours of one of theadministrations. In other embodiments, an effective amount ischaracterized as a near-lethal dose of the oxygen antagonist or otheractive compound. Likewise, a “near lethal collective dose” means anamount of multiple administrations of the oxygen antagonist or otheractive compound that is within 25% of the amount of the active compoundthat would cause at least a majority of cell(s) to die within 24 hoursof the one of the administrations. Also, a “supra-lethal collectivedose” means an amount of multiple administrations of the active compoundthat is at least 1.5 times the amount of the active compound that wouldcause at least a majority of cell(s) (or the entire organism) to diewithin 24 hours of the one of the administrations. It is contemplatedthat multiple doses can be administered so as to induce stasis in thewhole organism. The definition for “sub-lethal collective dose,”“near-lethal collective dose” and “supra-lethal collective dose” can beextrapolated based on the individual doses discussed earlier for stasisin whole organisms.

Biological matter may be exposed to or contacted with more than oneoxygen antagonist or other active compound. Biological matter may beexposed to at least one active compound, including 2, 3, 4, 5, 6, 7, 8,9, 10 or more oxygen antagonists or other active compound, or any rangederivable therein. With multiple active compounds, the term “effectiveamount” refers to the collective amount of active compounds. Forexample, the biological matter may be exposed to a first active compoundand then exposed to a second active compound. Alternatively, biologicalmatter may be exposed to more than one active compound at the same timeor in an overlapping manner. Furthermore, it is contemplated that morethan one active compounds may be comprised or mixed together, such as ina single composition to which biological matter is exposed. Therefore,it is contemplated that, in some embodiments, a combination of activecompounds is employed in compositions, methods, and articles ofmanufacture of the invention.

Biological matter may be provided with or exposed to an active compoundthrough inhalation, injection, catheterization, immersion, lavage,perfusion, topical application, absorption, adsorption, or oraladministration. Moreover, biological matter may be provided with orexposed to an active compound by administration to the biological matterintravenously, intradermally, intraarterially, intraperitoneally,intralesionally, intracranially, intraarticularly, intraprostaticaly,intrapleurally, intratracheally, intranasally, intrathecally,intravitreally, intravaginally, intrarectally, topically,intratumorally, intramuscularly, intraperitoneally, intraocularly,subcutaneously, subconjunctival, intravesicularlly, mucosally,intrapericardially, intraumbilically, intraocularally, orally,topically, locally, by inhalation, by injection, by infusion, bycontinuous infusion, by localized perfusion, via a catheter, or via alavage.

Methods and apparatuses of the invention involve a protective agent thatin some embodiments is an oxygen antagonist. In still furtherembodiments, the oxygen antagonist is a reducing agent. Additionally,the oxygen antagonist can be characterized as a chalcogenide compound.It will be understood that active compounds may also be protectiveagents. Moreover, any chalcogenide compound can be considered an activecompound so long as it achieves a goal of the invention, regardless ofwhether it is an oxygen antagonist.

In certain embodiments, the chalcogenide compound comprises sulfur,while in others, it comprises selenium, tellurium, or polonium. Incertain embodiments, a chalcogenide compound contains one or moreexposed sulfide groups. It is contemplated that this chalcogenidecompounds contains 1, 2, 3, 4, 5, 6 or more exposed sulfide groups, orany range derivable therein. In particular embodiments, such asulfide-containing compound is CS₂ (carbon disulfide).

Moreover, in some methods of the invention, stasis is induced in cell(s)by exposing the cell(s) to a reducing agent that has a chemicalstructure of (referred to as Formula I):

wherein X is N, O, Po, S, Se, or Te;

wherein Y is N or O;

wherein R₁ is H, C, lower alkyl, a lower alcohol, or CN;

wherein R₂ is H, C, lower alkyl, or a lower alcohol, or CN;

wherein n is 0 or 1;

wherein m is 0 or 1;

wherein k is 0, 1, 2, 3, or 4; and,

wherein p is 1 or 2.

The terms “lower alkyl” and “lower alcohol” are used according to theirordinary meanings and the symbols are the ones used to refer to chemicalelements. This chemical structure will be referred to as the “reducingagent structure” and any compound having this structure will be referredto as a reducing agent structure compound. In additional embodiments, kis 0 in the reducing agent structure. Moreover, in other embodiments,the R₁ and/or R₂ groups can be an amine or lower alkyl amine. In others,R₁ and/or R₂ could be a short chain alcohol or a short chain ketone.Additionally, R₁ and R₂ may be a linear of branched chain bridg and/orthe compound may be a cyclic compound. In still further embodiments, Xmay also be a halogen. The term “lower” is meant to refer to 1, 2, 3, 4,5, or 6 carbon atoms, or any range derivable therein. Moreover, R₁and/or R₂ may be other small organic groups, including, C₂-C₅ esters,amides, aldehydes, ketones, carboxylic acids, ethers, nitrites,anhydrides, halides, acyl halides, sulfides, sulfones, sulfonic acids,sulfoxides, and/or thiols. Such substitutions are clearly contemplatedwith respect to R₁ and/or R₂. In certain other embodiments, R₁ and/or R₂may be short chain versions of the small organic groups discussed above.“Short chain” means 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbonmolecules, or any range derivable therein.

It is contemplated that the reducing agent structure compound can be achalcogenide compound in some cases. In certain embodiments, thechalcogenide compound has an alkyl chain with an exposed chalcogenide.In others, the chalcogenide compound has a chalcogenide that becomesexposed once it is taken up by the biological matter. In this respect,the chalcogenide compound is similar to a prodrug as an oxygenantagonist. Therefore, one or more sulfur, selenium, oxygen, tellurium,polonium, or ununhexium molecules on the compound becomes availablesubsequent to exposure of the biological matter to the chalcogenidecompound. In this context, “available” means that the sulfur, selenide,oxygen, tellurium, polonium, or ununhexium will retain a negativecharge.

In certain embodiments, the chalcogenide is a salt, preferably saltswherein the chalcogen is in a −2 oxidation state. Sulfide saltsencompassed by embodiments of the invention include, but are not limitedto, sodium sulfide (Na₂S), sodium hydrogen sulfide (NaHS), potassiumsulfide (K₂S), potassium hydrogen sulfide (KHS), lithium sulfide (Li₂S),rubidium sulfide (Rb₂S), cesium sulfide (Cs₂S), ammonium sulfide((NH₄)₂S), ammonium hydrogen sulfide (NH₄)HS, beryllium sulfide (BeS),magnesium sulfide (MgS), calcium sulfide (CaS), strontium sulfide (SrS),barium sulfide (BaS), and the like. In like fashion, embodiments of thepresent invention encompass, but are not limited to, correspondingselenide and telluride salts. It is specifically contemplated that theinvention includes compositions containing a chalcogenide salt(chalcogenide compound that is a salt) with a pharmaceuticallyacceptable carrier or prepared as a pharmaceutically acceptableformulation. In still further embodiments, the reducing agent structurecompound is selected from the group consisting of H₂S, H₂Se, H₂Te, andH₂Po. In some cases, the reducing agent structure of Formula (I) has anX that is an S. In others, X is Se, or X is Te, or X is Po, or X is O.Furthermore, k in the reducing agent structure is 0 or 1 in someembodiments. In certain embodiments, the reducing agent structurecompound is dimethylsulfoxide (DMSO), dimethylsulfide (DMS), carbonmonoxide, methylmercaptan (CH₃SH), mercaptoethanol, thiocyanate,hydrogen cyanide, methanethiol (MeSH), or CS₂. In particularembodiments, the oxygen antagonist is H₂S, H₂Se, CS₂, MeSH, or DMS.Compounds on the order of the size of these molecules are particularlycontemplated (that is, within 50% of the average of their molecularweights).

In certain embodiments, a selenium-containing compound such as H₂Se isemployed. The amount of H₂Se may be in the range of 1 to 1000 parts perbillion in some embodiments of the invention. It is further contemplatedthat any embodiment discussed in the context of a sulfur-containingcompound may be implemented with a selenium-containing compound. Thisincludes substituting one of more sulfur atoms in a sulfur-containingmolecule with a corresponding selenium atom.

A further aspect of the invention encompasses compounds represented byFormula IV:

wherein:

-   -   X is N, O, P, Po, S, Se, Te, 0-0, Po—Po, S—S, Se—Se, or Te—Te;    -   n and m are independently 0 or 1; and    -   wherein R²¹ and R²² are independently hydrogen, halo, cyano,        phosphate, thio, alkyl, alkenyl, alkynyl, alkoxy, aminoalkyl,        cyanoalkyl, hydroxyalkyl, haloalkyl, hydroxyhaloalkyl,        alkylsulfonic acid, thiosulfonic acid, alkylthiosulfonic acid,        thioalkyl, alkylthio, alkylthioalkyl, alkylaryl, carbonyl,        alkylcarbonyl, haloalkylcarbonyl, alkylthiocarbonyl,        aminocarbonyl, aminothiocarbonyl, alkylaminothiocarbonyl,        haloalkylcarbonyl, alkoxycarbonyl, aminoalkylthio,        hydroxyalkylthio, cycloalkyl, cycloalkenyl, aryl, aryloxy,        heteroaryloxy, heterocyclyl, heterocyclyloxy, sulfonic acid,        sulfonic alkyl ester, thiosulfate, or sulfonamido; and    -   Y is cyano, isocyano, amino, alkyl amino, aminocarbonyl,        aminocarbonyl alkyl, alkylcarbonylamino, amidino, guanidine,        hydrazino, hydrazide, hydroxyl, alkoxy, aryloxy, hetroaryloxy,        cyloalkyloxy, carbonyloxy, alkylcarbonyloxy,        haloakylcarbonyloxy, arylcarbonyloxy, carbonylperoxy,        alkylcarbonylperoxy, arylcarbonylperoxy, phosphate,        alkylphosphate esters, sulfonic acid, sulfonic alkyl ester,        thiosulfate, thiosulfenyl, sulfonamide, —R²³R²⁴, wherein R²³ is        S, SS, Po, Po—Po, Se, Se—Se, Te, or Te—Te, and R²⁴ is defined as        for R²¹ herein, or Y is

wherein X, R²¹ and R²², are as defined herein.

Moreover, it is contemplated that in some embodiments of the invention,biological matter is provided with a precursor compound that becomes theactive version of the Formula I or IV compound by exposure to biologicalmatter, such as by chemical or enzymatic means. In addition, thecompound may be provided to the biological matter as a salt of thecompound., in the form of a free radical, or a negatively charged,positively charged or multiply charged species. Some compounds qualifyas both a Formula I and a Formula IV compound and in such cases, the useof the phrase “Formula I or Formula IV” is not intended to connote theexclusion of such compounds.

A compound identified by the structure of Formula I or Formula IV mayalso, in certain embodiments, be characterized as an oxygen antagonist,protective metabolic agent, or a precursor, prodrug, or salt thereof. Itis further contemplated that the compound need not be characterized assuch or qualify as such to be a compound used in the invention, so longas it achieves a particular method of the invention. In some otherembodiments, the compound may be considered a chalcogenide compound. Itis specifically contemplated that any compound identified by thestructure of Formula I or Formula IV or set forth in this disclosure maybe used instead of or in addition to an oxygen antagonist in methods,compositions, and apparatuses of the invention; similarly, anyembodiments discussed with respect to any of structure having Formula Ior Formula IV or otherwise set forth in this disclosure may be may beused instead of or in addition to an oxygen antagonist. Moreover, anycompound identified by the structure of Formulas I or IV or set forth inthis disclosure may be combined with any oxygen antagonist or any otheractive compound described herein. It is also contemplated that anycombination of such compounds may be provided or formulated together,sequentially (overlapping or nonoverlapping), and/or in an overlappingsequential manner (the administration of one compound is initiated andbefore that is complete, administration of another compound isinitiated) in methods, compositions, and other articles of manufactureof the invention to achieve the desired effects set forth herein. Incertain embodiments, more than one compound with the structure ofFormula I or Formula IV is provided. In certain embodiments, multipledifferent compounds with a structure from the same formula (i.e.,Formula I or Formula IV) are employed, while in other embodiments, whenmultiple different compounds are employed, they are from differentformulas.

In specific embodiments, it is contemplated that multiple activecompounds are used, wherein one of the compounds is carbon dioxide(CO₂). It is contemplated that at least one other compound is also aFormula I and/or Formula IV compound in some embodiments. In certaincases, carbon dioxide is provided to biological matter in combinationwith H₂S or an H₂S precursor (together, sequentially, or in anoverlapping sequential manner).

The amount of carbon dioxide to which the biological matter may beexposed are about, at least about, or at most about, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30% or more, or any range derivable therein. In certainembodiments, the amount is expressed in terms of ppm, such as about, atleast about, or at most about 350, 400, 500, 600, 700, 800, 900, 1000,1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200,2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400,3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600,4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000,13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000,23000, 24000, 25000, 26000, 27000, 28000, 29000, 30000, 31000, 32000,33000, 34000, 35000, 36000, 37000, 38000, 39000, 40000, 41000, 42000,43000, 44000, 45000, 46000, 47000, 48000, 49000, 50000, 60000, 70000,80000, 90000, 100000, 110000, 120000, 130000, 140000, 150000, 160000,170000, 180000, 190000, 200000, 210000, 220000, 230000, 240000, 250000,260000, 270000, 280000, 290000, 300000 or more ppm, or any rangederivable therein, as well as an molar equivalents. It is contemplatedthat these concentrations could apply to any other active compound ingaseous form.

In other embodiments, it is specifically contemplated that the activecompound is sodium sulfide, sodium thiomethoxide, cysteamine, sodiumthiocyanate, cysteamine-S-phosphate sodium salt, ortetrahydrothiopryan-4-ol. In additional embodiments, the active compoundis dimethylsulfoxide, thioacetic acid, selenourea,2-(3-Aminopropyl)-aminoethanethiol-dihydrogen-phosphate-ester,2-mercapto-ethanol, thioglycolicether, sodium selenide, sodium methanesulfinate, thiourea, or dimethylsulfide. It is specifically contemplatedthat these compounds, or any others discussed herein including anycompound with Formula I, II, III, or IV, may be provided or administeredto biological matter in an amount that is about, at least about, or atmost about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60,61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78,79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96,97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111,112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125,126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139,140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153,154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167,168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181,182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195,196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209,210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223,224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237,238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251,252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265,266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279,280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293,294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307,308, 309, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 320, 321,322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335,336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349,350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363,364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377,378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391,392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 403, 404, 405,406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419,420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433,434, 435, 436, 437, 438, 439, 440, 441, 442, 443, 444, 445, 446, 447,448, 449, 450, 451, 452, 453, 454, 455, 456, 457, 458, 459, 460, 461,462, 463, 464, 465, 466, 467, 468, 469, 470, 471, 472, 473, 474, 475,476, 477, 478, 479, 480, 481, 482, 483, 484, 485, 486, 487, 488, 489,490, 491, 492, 493, 494, 495, 496, 497, 498, 499, 500, 501, 502, 503,504, 505, 506, 507, 508, 509, 510, 511, 512, 513, 514, 515, 516, 517,518, 519, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, 531,532, 533, 534, 535, 536, 537, 538, 539, 540, 541, 542, 543, 544, 545,546, 547, 548, 549, 550, 551, 552, 553, 554, 555, 556, 557, 558, 559,560, 561, 562, 563, 564, 565, 566, 567, 568, 569, 570, 571, 572, 600,700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800,1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000,3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200,4300, 4400, 4500, 4600, 4700, 4800, 4900, 5000, 5100, 5200, 5300, 5400,5500, 5600, 5700, 5800, 5900, 6000, 6100, 6200, 6300, 6400, 6500, 6600,6700, 6800, 6900, 7000, 7100, 7200, 7300, 7400, 7500, 7600, 7700, 7800,7900, 8000, 8100, 8200, 8300, 8400, 8500, 8600, 8700, 8800, 8900, 9000,9100, 9200, 9300, 9400, 9500, 9600, 9700, 9800, 9900, 10000 mM ormmol/kg (of biological matter), or any range derivable therein.

It is specifically contemplated that any subset of active compoundsidentified by name or structure may be used in methods, compositions andarticles of manufacture. It is also specifically contemplated that anysubset of these compounds may be disclaimed as not constitutingembodiments of the invention. The present invention also concernspharmaceutical compositions comprising a therapeutically effectiveamount of one or more active compounds. It is understood that suchpharmaceutical compositions are formulated in pharmaceuticallyacceptable compositions. For example, the composition may include apharmaceutically acceptable diluent.

In certain embodiments, the pharmaceutical composition contains aneffective dose of an active to provide when administered to a patient aCmax or a steady state plasma concentration of the active compound toproduce a therapeutically effective benefit. In certain embodiments, theCmax or steady state plasma concentration to be achieved is about, atleast about, or at most about 0.01, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82,83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100,110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240,250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380,390, 400, 410, 420, 430, 440, 441, 450, 460, 470, 480, 490, 500, 510,520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650,660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790,800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930,940, 950, 960, 970, 980, 990, 1000, 1100, 1200, 1300, 1400, 1500, 1600,1700, 1800, 1900, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000μM or more, or any range derivable therein. In certain embodiments, suchas with H₂S, the desired Cmax or steady state plasma concentration isabout between 10 μM to about 10 mM, or between about 100 μM to about 1mM, or between about 200 μM to about 800 μM. Appropriate measures may betaken to consider and evaluate levels of the compound already in theblood, such as sulfur.

In certain embodiments, the pharmaceutical composition provides aneffective dose of H₂S to provide when administered to a patient a Cmaxor a steady state plasma concentration of between 10 μM to 10 mM,between about 100 μM to about 1 mM, or between about 200 μM to about 800μM. In relating dosing of hydrogen sulfide to dosing with sulfide salts,in typical embodiments, the dosing of the salt is based on administeringapproximately the same sulfur equivalents as the dosing of the H₂S.Appropriate measures will be taken to consider and evaluate levels ofsulfur already in the blood.

In certain embodiments, the composition comprises a gaseous form of oneor more of the active compounds specified above. In another embodiment,the composition comprises a salt of one or more of these compounds. Inone particular embodiment, a pharmaceutical composition comprises agaseous form of Formula I or IV or a salt of Formula I or IV. A gaseousform or salt of H₂S is specifically contemplated in some aspects of theinvention. It is contemplated that the amount of gas to which biologicalmatter is provided is about, at least about, or at most about 5, 10, 15,20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140,150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280,290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420,430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560,570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700,710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840,850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980,990, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000,2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200,3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400,4500, 4600, 4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000,11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000,21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, 30000,31000, 32000, 33000, 34000, 35000, 36000, 37000, 38000, 39000, 40000,41000, 42000, 43000, 44000, 45000, 46000, 47000, 48000, 49000, 50000,60000, 70000, 80000, 90000, 100000, 110000, 120000, 130000, 140000,150000, 160000, 170000, 180000, 190000, 200000, 210000, 220000, 230000,240000, 250000, 260000, 270000, 280000, 290000, 300000, 310000, 320000,330000, 340000, 350000, 360000, 370000, 380000, 390000, 400000 or moreppm, or any range derivable therein. Alternatively, the effective amountof gas(es) may be expressed as about, at least about, or at most about0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01,0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100%, or any rangederivable therein, with respect to the concentration in the air to whichthe biological matter is exposed. Moreover, it is contemplated that withsome embodiments, the amount of gas to which biological matter isprovided is about, at least about, or at most about 5, 10, 15, 20, 25,30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160,170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300,310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440,450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580,590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720,730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860,870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, 1000,1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200,2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400,3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600,4700, 4800, 4900, 5000, 6000, 7000, 8000, 9000, 10000 parts per billion(ppb) or any range derivable therein. In particular embodiments, theamount of hydrogen selenide provided to biological matter is on thisorder of magnitude.

In some embodiments of the invention, the pharmaceutical composition isa liquid. As discussed elsewhere, the composition may be a liquid withthe relevant compound(s) dissolved or bubbled into the composition. Insome cases, the pharmaceutical composition is a medical gas. Accordingto the United States Food and Drug Administration, “medical gases” arethose gases that are drugs within the meaning of §201(g)(1) of theFederal Food, Drug and Cosmetic Act (“the Act”) (21 U.S.C. §321(g) andpursuant to §503(b)(1)(A) of the Act (21 U.S.C. §353(b)(1)(A) arerequired to be dispensed by prescription. As such, such medical gasesrequire an appropriate FDA label. A medical gas includes at least oneactive compound.

The present invention further comprises apparatuses and articles ofmanufacture comprising packaging material and, contained within thepackaging material, an active stasis compound, wherein the packagingmaterial comprises a label that indicates that it can be used forinducing stasis in in vivo biological matter.

In some embodiments, the apparatus or article of manufacture furtherincludes a pharmaceutically acceptable diluent. In particular otherembodiments, the apparatus or article of manufacture has a bufferingagent. The active compound is provided in a first sealed container andthe pharmaceutically acceptable diluent is provided in a second sealedcontainer. In other embodiments, the device or article further hasinstructions for mixing the active compound and the diluent.Additionally, the active compound can be reconstituted for achieving anymethod of the invention, such as for inducing stasis in in vivobiological matter. It is contemplated that any label would specify theresult to be achieved and the use of the compound for patients in needof that result.

The present invention also concerns an article of manufacture comprisingpacked together: an active compound, instructions for use of the activestasis compound, comprising: (a) identifying in vivo tissue in need ofstasis treatment; and (b) administering an effective amount of theactive compound to the in vivo biological matter.

In further embodiments of the invention, there is an article ofmanufacture comprising a medical gas including an active compound and alabel comprising details or use and administration for inducing stasisin a biological matter or any other method of the invention.

The present invention also concerns kits and methods of using thesekits. In some embodiments, there are kits for the delivery of an activecompound to a tissue site in need of stasis treatment, or any othertreatment of the claimed invention, comprising: a drape adapted forforming a sealed envelope against a tissue site; a container comprisingan oxygen antagonist; and an inlet in the drape, wherein the containercomprising the active compound is in communication with the inlet. Incertain embodiments, the kit includes an outlet in the drape wherein theoutlet is in communication with a negative pressure source. In somecases, the drape comprises elastomeric material and/or has a pressuresensitive adhesive covering the periphery of the drape. The outlet maybe placed in fluid communication with the negative pressure source,which may or may not be a vacuum pump. There may also be a flexibleconduit communicating between the outlet and the negative pressuresource. In some embodiments, the kit includes a canister, which may ormay not be removable, in fluid communication between the outlet and thenegative pressure source. It is contemplated that the container includesan active compound that is in gaseous communication with the inlet. Incertain embodiments, the container includes an active compound that is agas or a liquid gas. The kit may also include a vaporizer incommunication between the container comprising an oxygen antagonist andthe inlet. In addition, it may have a return outlet in communicationwith the container comprising the active compound.

In particular embodiments, the active compound in the kits is carbonmonoxide, carbon dioxide, H₂Se, and/or H₂S. In certain embodiments, thetissue site for which the kit or method is applied is wounded.

Moreover, it will be generally understood that any compound discussedherein as an oxygen antagonist can be provided in prodrug form to thebiological matter, meaning that the biological matter or othersubstance(s) in the environment of the biological matter alters theprodrug into its active form, that is, into an oxygen antagonist. It iscontemplated that the term “precursor” covers compounds that areconsidered “prodrugs.”

The oxygen antagonist or other active compound may be or may be providedas a gas, semi-solid liquid (such as a gel or paste), liquid, or solid.It is contemplated that biological matter may be exposed to more thanone such active compound and/or to that active compound in more than onestate. Moreover, the active compound may be formulated for a particularmode of administration, as is discussed herein. In certain embodiments,the active compound is in pharmaceutical acceptable formulation forintravenous delivery.

In certain embodiments, the active compound is a gas. In particularembodiments, the gaseous active compound includes carbon monoxide,carbon dioxide, nitrogen, sulfur, selenium, tellurium, or polonium, or amixture thereof. Moreover, it is specifically contemplated that theactive compound is a chalcogenide compound as a gas. In someembodiments, the active compound is in a gas mixture comprising morethan one gas. The other gas(es) is a non-toxic and/or a non-reactive gasin some embodiments. In some embodiments, the other gas is a noble gas(helium, neon, argon, krypton, xenon, radon, or ununoctium), nitrogen,nitrous oxide, hydrogen, or a mixture thereof. For instance, thenon-reactive gas may simply be a mixture that constitutes “room air,”which is a mixture of nitrogen, oxygen, argon and carbon dioxide, aswell as trace amounts of other molecules such as neon, helium, methane,krypton, and hydrogen. The precise amounts of each varies, though atypical sample might contain about 78% nitrogen, 21% oxygen, 0.9% argon,and 0.04% carbon dioxide. It is contemplated that in the context of thepresent invention, “room air” is a mixture containing about 75 to about81% nitrogen, about 18 to about 24% oxygen, about 0.7 to about 1.1%argon, and about 0.02% to about 0.06% carbon dioxide. A gaseous activecompound may be first diluted with a non-toxic and/or non-reactive gasprior to administration or exposure to biological matter. Additionallyor alternatively, any gaseous active compound may be mixed with room airprior to administration or exposure to biological matter or the compoundmay be administered or exposed to the biological matter in room air.

In some instances, the gas mixture also contains oxygen. An activecompound gas is mixed with oxygen to form an oxygen gas (O₂) mixture inother embodiments of the invention. Specifically contemplated is anoxygen gas mixture in which the amount of oxygen in the oxygen gasmixture is less than the total amount of all other gas or gases in themixture.

In some embodiments, the active compound gas is carbon monoxide and theamount of carbon monoxide is about the same or exceeds any amount ofoxygen in the oxygen gas mixture. In particular embodiments, carbonmonoxide is employed with blood-free biological matter. The term“blood-free biological matter” refers to cells and organs whoseoxygenation is not dependent, or no longer dependent, on thevasculature, such as an organ for transplant. Preferably, the atmospherewill be 100% CO, but as will be evident to one skilled in the art, theamount of CO may be balanced with gases other than oxygen providing thatthe amount of usable oxygen is reduced to a level that prevents cellularrespiration. In this context, the ratio of carbon monoxide-to-oxygen ispreferably 85:15 or greater, 199:1 or greater or 399:1 or greater. Incertain embodiments, the ratio is about, at least about, or at mostabout 1:1, 2:1, 2.5:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1,20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1,80:1, 85:1, 90:1, 95:1, 100:1, 110:1, 120:1, 130:1, 140:1, 150:1, 160:1,170:1, 180:1, 190:1, 200:1, 210:1, 220:1, 230:1, 240:1, 250:1, 260:1,270:1, 280:1, 290:1, 300:1, 310:1, 320:1, 330:1, 340:1, 350:1, 360:1,370:1, 380:1, 390:1, 400:1, 410:1, 420:1, 430:1, 440:1, 450:1, 460:1,470:1, 480:1, 490:1, 500:1 or more, or any range derivable therein.

In still further embodiments, the above numbers pertain to the ratio ofcarbon monoxide to a mixture of oxygen and one or more other gases. Insome cases, it is contemplated that the other gas is a nonreactive gassuch as nitrogen (N₂). Thus, in other embodiments of the invention, theabove numbers apply to ratios of carbon monoxide to a combination ofoxygen and nitrogen (O₂/N₂) that can be used in methods and apparatusesof the invention. Accordingly, it will be understood that other gasesmay or may not be present. In some embodiments, the CO:oxygen ratio isbalanced with one or more other gases (non-carbon monoxide andnon-oxygen gases). In particular embodiments, the CO:oxygen ratio isbalanced with nitrogen. In still further embodiments, the amount of COis a ratio of CO compared to room air, as is described by the numbersabove.

In some cases, the amount of carbon monoxide is relative to the amountof oxygen, while in others, it is an absolute amount. For example, insome embodiments of the invention, the amount of oxygen is in terms of“parts per million (ppm)” which is a measure of the parts in volume ofoxygen in a million parts of air at standard temperature and pressure of20° C. and one atmosphere pressure and the balance of the gas volume ismade up with carbon monoxide. In this context, the amount of carbonmonoxide to oxygen is related in terms of parts per million of oxygenbalanced with carbon monoxide. It is contemplated that the atmosphere towhich the biological material is exposed or incubated may be at least 0,50, 100, 200, 300, 400, 500, 1000, or 2000 parts per million (ppm) ofoxygen balanced with carbon monoxide and in some cases carbon monoxidemixed with a non-toxic and/or non-reactive gas The term “environment”refers to the immediate environment of the biological matter, that is,the environment with which it is in direct contact. Thus, the biologicalmaterial must be directly exposed to carbon monoxide, and it isinsufficient that a sealed tank of carbon monoxide be in the same roomas the biological matter and be considered to be incubated an“environment” according to the invention. Alternatively, the atmospheremay be expressed in terms of kPa. It is generally understood that 1million parts=101 kPa at 1 atmosphere. In embodiments of the invention,the environment in which a biological material is incubated or exposedto is about, at least about, or at most about 0.001, 0.005, 0.01, 0.02,0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14,0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26,0.27, 0.28, 0.29, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70,0.75, 0.80, 0.5, 0.90, 0.95, 1.0 kPa or more O₂, or any range derivabletherein. As described above, such levels can be balanced with carbonmonoxide and/or other non-toxic and/or non-reactive gas(es) Also, theatmosphere may be defined in terms of CO levels in kPa units. In certainembodiments, the atmosphere is about, at least about, or at most about1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,90, 95, 101, 101.3 kPa CO, or any range derivable therein. In particularembodiments, the partial pressure is about or at least about 85, 90, 95,101, 101.3 kPa CO, or any range derivable therein.

The amount of time the sample is incubated or exposed to carbon monoxidecan also vary in embodiments of the invention. In some embodiments, thesample is incubated or exposed to carbon monoxide for about, for atleast about, or for at most about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,52, 53, 54, 55, 56, 57, 58, 59, 60 or more minutes and/or, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24 hours, and/or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more days.

In some embodiments, the invention concerns compositions and articles ofmanufacture that contain one or more active compounds. In certainembodiments, a composition has one or more of these active compounds asa gas that is bubbled in it so that the composition provides thecompound to the biological matter when it is exposed to the composition.Such compounds may be gels, liquids, or other semi-solid material. Incertain embodiments, a solution has an oxygen antagonist as a gasbubbled through it. It is contemplated that the amount bubbled in thegas will provide the appropriate amount of the compound to biologicalmaterial exposed to the solution. In certain embodiments, the amount ofgas bubbled into the solution is about, at least about, or at most about0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0,7.5, 8.0, 8.5, 9.0, 9.5, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25,30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 times ormore, or any range derivable therein, than the amount to which thebiological matter is effectively provided.

Biological matter is exposed to the gas in a closed container in someembodiments of the invention. In some cases, the closed container canmaintain a particular environment or modulate the environment as isdesired. The environment refers to the amount of oxygen antagonist thatthe biological matter is exposed and/or the temperature, gascomposition, or pressure of the environment. In some cases, thebiological matter is placed under a vacuum before, during, or afterexposure to an oxygen antagonist or other active compound. Moreover, inother cases, the biological matter is exposed to a normoxic environmentafter being exposed to an oxygen antagonist or other active compound. Incertain embodiments, the present invention includes methods for inducingstasis or protecting biological matter from injury or disease thatinclude providing an active compound to the biological matter incombination with providing another stasis-inducing active compound orenvironmental condition to the biological matter. Such combinationtreatment may occur in any order, e.g., simultaneously or sequentially.In certain embodiments, an active compound is provided to biologicalmatter, and the biological matter is subsequently placed under hypoxicconditions, such as 5% O₂, or sequentially exposed to increasinglyhypoxic conditions, such as 5% O₂ followed by 4% O₂, 3% O₂, 2% O₂, 1%O₂, or O₂-free conditions, or any sequential combination of suchconditions.

Moreover, in other embodiments, the environment containing thebiological matter cycles at least once to a different amount orconcentration of the oxygen antagonist or other active compound, whereinthe difference in amount or concentration is by at least one percentagedifference. The environment may cycle back and forth between one or moreamounts or concentrations of the oxygen antagonist or other activecompound, or it may gradually increase or decrease the amount orconcentrations of an that compound. In some cases, the different amountor concentration is between about 0 and 99.9% of the amount orconcentration of the oxygen antagonist or other active compound to whichthe biological matter was initially exposed. It is contemplated that thedifference in amount and/or concentration is about, at least about, orat most about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41,42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77,78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95,96, 97, 98, 99% or more, or any range derivable therein.

Methods of the invention can also include a step of subjectingbiological matter to a controlled temperature environment. In certainembodiments, the biological matter is exposed to a temperature that is a“nonphysiological temperature environment,” which refers to atemperature in which the biological matter cannot live in for more than96 hours. The controlled temperature environment can have a temperatureof about, at least about, or at most about −210, −200, −190, −180, −170,−160, −150, −140, −130, −120, −110, −100, −90, −80, −70, −60, −50, −40,−30, −20, −10, −5, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104,105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118,119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132,133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146,147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160,161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174,175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188,189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200° C. or more,or any range derivable therein. Biological matter may also be exposed toan oxygen antagonist or other active compound at room temperature, whichmeans a temperature between about 20° C. and about 25° C. Furthermore,it is contemplated the biological matter achieves a core temperature ofany amount or range of amounts discussed.

It is contemplated that the biological matter can be subjected to anonphysiological temperature environment or a controlled temperatureenvironment before, during or after exposure to the oxygen antagonist(s)or other active compound(s). Furthermore, in some embodiments, thebiological matter is subjected to a nonphysiological temperatureenvironment or a controlled temperature environment for a period of timebetween about one minute and about one year. The amount of time may beabout, at least about, or at most about 30 seconds, 1, 2, 3, 4, 5, 10,15, 20, 25, 30, 35, 40, 45, 50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2,3, 4, 5, 6, 7 days, 1, 2, 3, 4, 5 weeks, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12 months, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20 or more years, and any combination or range derivabletherein. Moreover, there may also be a step of increasing the ambienttemperature relative to the reduced temperature.

Moreover, it is contemplated that the temperature may be altered orcycled during the process in which temperature is controlled. In someembodiments, the temperature of the biological matter may first bereduced before it is placed in the environment that has the oxygenantagonist or other active compound, while in others, the biologicalmatter may be cooled by placing it in the environment with the activecompound, that is below the temperature of the biological matter. Thebiological matter and/or environment may be cooled or heated gradually,such that the temperature of the biological matter or environment startsat one temperature but then reaches another temperature.

Methods of the invention can also include a step of subjectingbiological matter to a controlled pressure environment. In certainembodiments, the biological matter is exposed to pressure that is lowerthan the pressure under which the organism is typically under. Incertain embodiments, the biological matter is subjected to a“nonphysiological pressure environment,” which refers to a pressureunder which the biological matter cannot live under for more than 96hours. The controlled pressure environment can have a pressure of about,at least about, or at most 10⁻¹⁴, 10⁻¹³, 10⁻¹², 10⁻¹¹, 10⁻¹¹, 10⁻¹⁰,10⁻⁹, 10⁻⁸, 10⁻⁷, 10⁻⁶, 10⁻⁵, 10⁻⁴, 10⁻³, 10⁻², 10⁻¹, 0.2, 0.3, 0.4 or0.5 atm or more, or any range derivable therein.

It is contemplated that the biological matter can be subjected to anonphysiological pressure environment or a controlled pressureenvironment before, during or after exposure to the active compound(s).Furthermore, in some embodiments, the biological matter is subjected toa nonphysiological pressure environment or a controlled pressureenvironment for a period of time between about one minute and about oneyear. The amount of time may be about, at least about, or at most about30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,19, 20, 21, 22, 23, 24 hours, 1, 2, 3, 4, 5, 6, 7 days, 1, 2, 3, 4, 5weeks, 1,2,3,4,5,6,7,8,9,10, 11, 12 months, 1,2,3,4,5,6,7,8,9,10, 11,12, 13, 14, 15, 16, 17, 18, 19, 20 or more years, and any combination orrange derivable therein.

Moreover, it is contemplated that the pressure may be altered or cycledduring the process in which pressure is controlled. In some embodiments,the pressure to which the biological matter is exposed may first bereduced before it is placed in the environment that has the activecompound, while in others, the biological matter placed under pressureafter exposure to an active compound. The pressure may be reducedgradually, such that the pressure of the environment starts at onepressure but then reaches another pressure within 10, 20, 30, 40, 50, 60seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 minutes,1,2,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21,22, 23, 24 hours, and/or 1, 2, 3, 4, 5, 6, 7 days or more, and anycombination or range derivable therein. In certain embodiments, methodsinclude modulating environmental oxygen levels or removing thebiological material from an environment having oxygen. Operationally,exposing biological material to an environment in which oxygen isdiminished or absent may mimic exposure of the biological material to anoxygen antagonist. It is contemplated that in some embodiments of theinvention, biological matter is exposed to or provided with an activecompound under conditions in which the environment of the biologicalmatter is hypoxic or anoxic, as described in further detail below. Thismay be intentional or nonintentional. Thus, in some embodiments of theinvention, biological matter is intentionally placed in an environmentthat is anoxic or hypoxic or in an environment that is made anoxic orhypoxic. In other embodiments, the biological matter is under suchconditions as a result of an unintended situation, for example, if thebiological matter is under ischemic or potentially ischemic conditions.Therefore, it is contemplated in some cases that the hypoxic or anoxicconditions would damage the matter in the absence of the activecompound.

In certain methods of the invention, there also is a step of assessingthe level of the oxygen antagonist and/or oxidative phosphorylation inthe biological matter in which stasis was induced. Moreover, in someembodiments of the invention, there is a step of assessing the level ofcellular metabolism that is generally occurring in the biologicalmatter. In some cases, the amount of the active compound in thebiological matter is measured and/or a reduction in the temperature ofthe biological matter is assessed. Moreover, in some methods of theinvention, the extent of one or more therapeutic effects is evaluated.

In certain other embodiments, any toxicity effect on the biologicalmatter from an active compound and/or environmental change (temperature,pressure) is monitored or controlled for. It is contemplated thattoxicity can be controlled for by altering the level, amount, duration,or frequency of an active compound and/or environmental change to whichthe biological matter is exposed. In certain embodiments the alterationis a reduction, while in certain other embodiments, the alteration is anincrease. It is contemplated that the skilled artisan is aware of anumber of ways of evaluating toxicity effects in biological matter.

Other optional steps for methods of the invention include identifying anappropriate active compound; diagnosing the patient; taking a patienthistory and/or having one or more tests done on the patient prior toadministering or prescribing an active compound to the patient.

Compositions, methods, and articles of manufacture of the invention canbe used on biological matter that will be transferred back into thedonor organism from which it was derived (autologous) or a differentrecipient (heterologous) subject. In some embodiments, biological matteris obtained directly from a donor organism. In others, the biologicalmatter is placed in culture prior to exposure to an oxygen antagonist orother active compound. In some situations, the biological matter isobtained from a donor organism administered extracorporeal membraneoxygenation prior to retrieval of the biological matter, which is atechnique implemented to aid in the preservation of biological matter.Moreover, methods include administering or implanting the biologicalmatter in which stasis was induced to a live recipient organism.

Methods of the invention also concern inducing stasis in in vivobiological matter comprising incubating the biological matter with anoxygen antagonist or other active compound that creates hypoxicconditions for an effective amount of time for the biological matter toenter stasis.

Furthermore, other embodiments of the invention include methods ofreducing oxygen demand in in vivo biological matter comprisingcontacting the biological matter with an effective amount of an oxygenantagonist or other active compound to reduce their oxygen demand. It iscontemplated that oxygen demand is reduced about, at least about, or atmost about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100%, or any range derivabletherein, with respect to the amount of oxygen demand in cells of thebiological matter or a representative sample of cells from thebiological matter not exposed or no longer exposed to the oxygenantagonist or other active compound.

Other aspects of the invention concern methods for preserving in vivobiological matter comprising exposing the in vivo biological matter toan effective amount of an oxygen antagonist or other active compound topreserve the biological matter in vivo.

The present invention also concerns a method of delaying or reducing theeffects of trauma on or in an organism comprising exposing biologicalmatter at risk for trauma to an effective amount of an oxygen antagonistor other active compound.

In other aspects of the invention, there are methods for treating orpreventing hemorrhagic shock in a patient comprising exposing thepatient to an effective amount of an oxygen antagonist or other activecompound. Alternatively, in some embodiments methods prevents lethalityin the patient as a result of the bleeding and/or hemorrhagic shock. Insuch methods of preventing a patient from bleeding to death or preventlethality in a bleeding patient, steps include exposing the patient toan effective amount of an oxygen antagonist or other active compound. Incertain embodiments, the oxygen antagonist is specifically contemplatedto be a chalcogenide compound such as H₂S.

Methods for reducing heart rate in an organism are also included as partof the invention. Such methods involve contacting the biological sampleor organism with an effective amount of an oxygen antagonist or otheractive compound.

One embodiment of the invention relates to a method of inducinghibernation in a mammal comprising contacting the mammal with aneffective amount of an oxygen antagonist or other active compound.

In another embodiment, there is a method of anesthetizing an organismcomprising exposing biological matter in which anesthesia is desired toan effective amount of an oxygen antagonist or other active compound. Itis contemplated that the anesthesia may be similar to local or generalanesthesia.

The present invention further includes methods of protecting a mammalfrom radiation therapy or chemotherapy comprising contacting the mammalwith an effective amount of an oxygen antagonist or other activecompound prior to or during radiation therapy or chemotherapy. Withlocal administration of the cancer therapy, it is specificallycontemplated that the oxygen antagonist or other active compound mayalso be administered locally to the affected organ, tissue, and/orcells. In certain embodiments, methods can be used for preventing orreducing hair loss in a chemotherapy patient. It is contemplated thatsuch a patient may have already received chemotherapy or be a candidatefor chemotherapy. In particular cases, it is contemplated that an activecompound is provided to the patient as a topical gel to be applied wherethe hair loss is anticipated or present.

The present invention also covers reducing the oxygen requirement ofbiological matter, meaning that the amount of oxygen required by thebiological matter to survive is reduced. This can be achieved byproviding an effective amount of one or more active compounds. It isgenerally known how much oxygen particular biological matter require tosurvive, which can also be dependent on time, pressure, and temperature.In certain embodiments of the invention, the oxygen requirement of thebiological matter is reduced by about, at least about, or at most about1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56,57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74,75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92,93, 94, 95, 96, 97, 98, 99, 100%, or any range derivable therein, ascompared to the requirement of the biological matter in the absence ofthe effective amount of the active compound(s).

In additional embodiments, there are methods of treating ahyperproliferative disease (e.g., cancer) in a mammal comprisingcontacting the mammal with an effective amount of an oxygen antagonistor other active compound and subjecting the mammal to hyperthermiatherapy.

While methods of the invention may be applied to preserving organs fortransplant, other aspects of the invention concern the recipientorganism. In some embodiments, there are methods of inhibiting rejectionof an organ transplant in a mammal comprising providing the mammal withan effective amount of an oxygen antagonist or other active compound.

Temperature regulation can be achieved in organisms by employing oxygenantagonists or other active compounds. In some embodiments, there is amethod of treating a subject with hypothermia comprising (a) contactingthe subject with an effective amount of an oxygen antagonist, and then(b) subjecting the subject to an environmental temperature above that ofthe subject. In other embodiments, the present invention includes amethod of treating a subject with hyperthermia comprising (a) contactingthe subject with an effective amount of an oxygen antagonist or otheractive compound. In some cases, treatment of hyperthermia also includes(b) subjecting the subject to an environmental temperature that is atleast about 20° C. below that of the subject. As discussed above,exposing the subject to nonphysiological or a controlled temperatureenvironment can be used in additional embodiments. It is contemplatedthat this method may be achieved with active compounds generally.

In some cases, the invention concerns a method for inducing cardioplegiain a patient undergoing bypass surgery comprising administering to thepatient an effective amount of an oxygen antagonist or other activecompound. It is contemplated that administration may be local to theheart so as to protect it.

Other aspects of the invention relate to a method for preventinghematologic shock in a patient comprising administering to the patientan effective amount of an oxygen antagonist or other active compound.

Moreover, there are methods for promoting wound healing in an organismcomprising administering to the organism or wound an effective amount ofan oxygen antagonist or other active compound.

In addition, the present invention covers a method for preventing ortreating neurodegeneration in a mammal comprising administering to themammal an effective amount of an oxygen antagonist or other activecompound.

The present invention also covers reducing the oxygen requirement ofbiological matter, meaning that the amount of oxygen required by thebiological matter to survive is reduced. This can be achieved byproviding an effective amount of one or more active compounds. It isgenerally known how much oxygen particular biological matter require tosurvive, which can also be dependent on time, pressure, and temperature.In certain embodiments of the invention, the oxygen requirement of thebiological matter is reduced by about, at least about, or at most about1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56,57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74,75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92,93, 94, 95, 96, 97, 98, 99, 100%, or any range derivable therein, ascompared to the requirement of the biological matter in the absence ofthe effective amount of the active compound(s).

Additional embodiments of the invention concern methods for preventinghair loss, such as from chemotherapy, by administering to a patient whohas or will undergo chemotherapy an effective amount of at least oneactive compound.

In cases in which biological matter is being protected from damage orfurther damage, it is contemplated that the biological matter may beexposed to an oxygen antagonist within about, within at least about, orwithin at most about 30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35,40, 45, 50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2, 3, 4, 5, 6, 7 days,1, 2, 3, 4, 5 weeks, 1,2,3,4,5,6,7,8,9,10, 11, 12 months,1,2,3,4,5,6,7,8,9,10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or moreyears, and any combination or range derivable therein, after initialdamage (trauma or wound or degeneration) occurs. Thus in additionalembodiments of the invention, methods include an initial assessment ofany damage, trauma, a wound, or degeneration.

In certain embodiments of the invention there are methods for treating apatient affected with a hematological disorder, which means a disease,disorder or condition that affects any hematopoietic cells or tissue.Examples include sickle cell disease and thalassemia. Thus, in someembodiments, there are methods of treating a patient with sickle celldisease or thalassemia with an effective amount of an active compound.In other embodiments, there are methods for enhancing survivability in apatient with cystic fibrosis (CF) by administering or providing aneffective amount of an active compound. In other methods of theinvention, there are methods for treating cynanide poisoning in asubject comprising administering an effective amount of an activecompound. In certain embodiments, the compound is H₂S.

Other aspects of the invention concern methods for preserving one ormore cells that are separate from an organism comprising contacting thecell(s) with an effective amount of an oxygen antagonist or other activecompound to preserve the one or more cells. In addition to the cells andcell types discussed above and elsewhere in this application, it iscontemplated that shrimp embryos are specifically contemplated for usewith the present invention.

Moreover, in some embodiments of the invention, there are methods forpreserving platelets. Shortcomings of the prior art are reduced oreliminated using techniques of this disclosure. Embodiments concerningplatelets and oxygen reduction find wide application including but notlimited to any application that would benefit from longer-lastingstorage of platelets.

In one embodiment, oxygen reduction techniques can be embodied in a kit.For example, the kit currently sold under product number 261215,available from Becton Dickinson, makes use of select techniquesdescribed here. That kit includes an anaerobic generator (e.g., ahydrogen gas generator), Palladium Catalysts, an anaerobic indicator,and a gas impermeable, sealable, “BioBag” into which the abovecomponents (together with platelets in a gas-permeable bag) are placedand sealed.

In other embodiments of the invention, there are methods for reversiblyinhibiting metabolism of a cell and/or organism by providing aneffective amount of an active compound. It is specifically contemplatedthat rotenone is not the compound employed in this method, or possiblyother methods of the invention. Moreover, it is also contemplated thatin some embodiments, rotenone is excluded as an active compound.Similarly, it is contemplated that nitric oxide may be excluded as anactive compound.

In other embodiments of the invention, methods are provided forenhancing the ability of biological matter to enter stasis in responseto an injury or disease by providing an effective amount of an activecompound, thereby protecting the biological matter from damage orinjury, thereby enhancing survival of biological matter. Relatedembodiments include methods of preparing or priming biological matterfor entry into stasis in response to an injury or disease by providingan effective amount of an active compound. Other related embodimentsinclude method of inducing biological matter into pre-stasis, therebyprotecting the biological matter from damage or injury. For example,treatment with an active compound at a dosage or for a time less thanrequired to induce stasis enables the biological matter to more readilyor more completely achieve a beneficial state of stasis in response toan injury or disease, while in the absence of treatment with the activecompound, the biological matter would die or suffer damage or injurybefore it reached a protective level of stasis, e.g., a level sufficientto render the biological matter resistant to lethal hypoxia.

Certain injuries and disease states cause biological matter to reduceits metabolism and/or temperature to degrees that may not achievestasis. For example, hypoxia, ischemia, and blood loss all reduce theamount of oxygen available and supplied to oxygen utilizing biologicalmatter, thereby reducing oxygen utilization in cells of the biologicalmatter, reducing energy production derived from oxidativephosphorylation, and thereby decreasing thermogenesis, leading tohypothermia. Depending on the severity or time elapsed following theonset or progression of the injurious or disease insult, “stasis” may ormay not have been achieved. Treatment with an active compound lowers thethreshold (i.e., the severity or duration of the insult that is neededto achieve stasis) for induction of stasis, or it may add to orsynergize with the injurious or disease stimuli to induce stasis inbiological matter under injurious conditions that would not haveresulted in stasis were it not for the active compound treatment. Suchactivity of active compounds is determined by comparing thestasis-inducing effects (magnitude, kinetics) of injurious or diseasestimuli alone with those in which the biological matter was pre-exposed,exposed concomitantly, exposed after, or any combination thereof, to theactive compound. For example, as described in Example 11 of the instantpatent application, pre-exposure of mice to 150 ppm H₂S in air caused anapproximately two-fold drop in CO₂ production prior to exposure tohypoxia (5% O₂). Subsequently, CO₂ production in pre-treated mice fellapproximately 50-fold during hypoxia. In contrast, while CO₂ productionin control, H₂S untreated mice also fell, the hypoxia survivability ofthe mice was not achieved, presumably since the mice died before stasiswas achieved.

In other aspects of the invention, there are methods for inducing sleepin an organism comprising exposing the organism to an effective amountof an active compound, wherein the effective amount is less than anamount that can induce stasis in the organism. The term “sleep” is usedaccording to its ordinary and plain meaning in a medical context. Sleepis distinguishable from other states of unconsciousness, which are alsocontemplated as states that can be achieved using methods of theinvention.

The present invention also concerns methods for anesthetizing biologicalmatter comprising exposing the matter to an effective amount of anactive compound, wherein the effective amount is less than an amountthat can induce stasis in the organism.

In the methods discussed above, an effective amount that is less than anamount that can induce stasis in an organism may be reduced with respectto duration and/or amount. That reduction may be a reduction in amountby 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,92, 93, 94, 95, 96, 97, 98, 99 percent, or any range derivable therein,of the amount to induce stasis. A reduction may be a reduction induration (length of exposure time) by 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15,20, 25, 30, 35, 40, 45, 50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2, 3,4, 5, 6, 7, days, 1, 2, 3, 4, 5 weeks, and/or 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12 months, or any range derivable therein. Alternatively, thereduction may be in terms of the overall effective amount provided tothe biological matter, which may be a reduction of 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,98, 99 percent, or any range derivable therein, relative to the overalleffective amount to induce stasis in an organism of that species and/orsize.

It is specifically contemplated that the present invention can be usedfor preserving organisms that are used for consumption or laboratoryresearch, such as flies, frogs, fish, mice, rats, dogs, shrimp, andembryos thereof.

Methods of the invention can involve employing an apparatus or systemthat maintains the environment in which biological matter is placed orexposed to. The invention includes an apparatus in which an oxygenantagonist or other active compound, particularly as a gas, is supplied.In some embodiments, the apparatus includes a container with a samplechamber for holding the biological matter, wherein the container isconnected to a supply of gas comprising the oxygen antagonist(s). It isspecifically contemplated that the container may be a solid container orit may flexible, such as a bag.

In some embodiments, the invention is an apparatus for preservingcell(s), the apparatus comprising: a container having a sample chamberwith a volume of no greater than 775 liters; and a first gas supply influid communication with the sample chamber, the first gas supplyincluding carbon monoxide. In further embodiments, the apparatus alsoincludes a cooling unit that regulates the temperature inside the samplechamber and/or a gas regulator that regulates the amount of oxygenantagonist or other active compound in the chamber or the amount ofoxygen antagonist or other active compound in a solution that is in thechamber.

It is contemplated that there may be a gas supply for a second oradditional gas or a second or additional gas supply for the oxygenantagonist or other active compound. The second gas supply may beconnected with the sample chamber or it may be connected with the firstgas supply. The additional gas, as discussed above, may be a non-toxicand/or non-reactive gas.

A gas regulator is part of the apparatus in some embodiments of theinvention. One, two, three, or more gas regulators may be employed. Insome cases, the gas regulator regulates the gas supplied to the samplechamber from the first gas supply. Alternatively, it regulates the gassupplied to the sample chamber or first gas supply from the second gassupply, or there may be a regulator for both the first and second gassupplies. It is further contemplated that any gas regulator can beprogrammed to control the amount of gas supplied to the sample chamberand/or to another gas supply. The regulation may or may not be for aspecified period of time. There may be a gas regulator, which may or maynot be programmable, for any gas supply directly or indirectly connectedto the sample chamber. In some cases, the gas regulator iselectronically programmable.

In some cases, the pressure and/or the temperature inside the chambercan be regulated with either a pressure regulator or temperatureregulator, respectively. As with the gas regulator, these regulators maybe electronically programmable. The apparatus of the invention may alsohave a cooling and/or heating unit to achieve the temperatures discussedabove. The unit may or may not be electronically programmable.

In additional embodiments, the apparatus includes a wheeled cart onwhich the container rests or it may have one or more handles.

It is specifically contemplated that the invention includes an apparatusfor cell(s), tissues, organs, and even whole organisms, in which theapparatus has: a container having a sample chamber; a first gas supplyin fluid communication with the sample chamber, the first gas supplyincluding the oxygen antagonist(s) or other active compound(s); and anelectronically-programmable gas regulator that regulates gas supplied tothe sample chamber from the first gas supply.

In some embodiments, the apparatus also has a structure configured toprovide a vacuum within the sample chamber.

Moreover, any oxygen antagonist or other active compound described inthis application is contemplated for use with apparatuses of theinvention. In specific embodiments, carbon monoxide can be administeredusing this apparatus. In other cases, a chalcogenide compound can beadministered or a compound having the reducing agent structure. In stillfurther embodiments, an active compound is administered using theapparatus. In specific embodiments, the invention covers a device or itsuse. In certain embodiments, the device is single dose delivery device.In other embodiments, the device is an inhaler or nebulizer. In evenfurther embodiments, other devices include, but are not limited to, aninjection device such as a pen, a pump such as an infusion pump, or apatch. Moreover, it is contemplated that these devices may or may not besingle dose delivery devices.

Additionally, the present invention concerns screening assays. In someembodiments, a candidate substance is screened for the ability to act asan oxygen antagonist or active compound, specifically including aprotective metabolic agent. This can be done using any assay describedherein, such as by measuring carbon dioxide output. Any substanceidentified as having exhibiting characteristics of an oxygen antagonistor other active compound can be further characterized or tested.Moreover, it is contemplated that such a substance can be administeredto biological matter to induce stasis or manufactured thereafter.

In certain embodiments, there are screening methods for activecompounds, including active stasis compounds. Furthermore, the methodsof screening may be for oxygen antagonists or for any other compoundsthat can effect the methods discussed herein. In some embodiments, thereare screening methods involving a) exposing a zebrafish embryo to asubstance; b) measuring the heart rate of the embryo; c) comparing theheart rate of the embryo in the presence of the substance to the heartrate in the absence of the substance, wherein a reduction of heart rate,such as by 50% or more, identifies the substance as a candidate activecompound. Instead of zebrafish embryos, it is contemplated that othernon-human organisms may be used as well, such as fish, frogs, flies,shrimp, or their embryos. In further embodiments, the heart rate of theembryo is measured by counting the number of heartbeats. This can bedone, in some cases, by viewing the embryo under a dissectingmicroscope.

Other screening embodiments involve: a) exposing a nematode to asubstance; b) assaying one or more of the following cellular respirationfactors: i) core body temperature; ii) oxygen consumption; iii)motility; or, iv) carbon dioxide production; c) comparing the cellularrespiration factor of the nematode in the presence of the substance tothe cellular respiration factor in the absence of the substance, whereina reduction of the characteristic identifies the substance as acandidate active compound. It is specifically contemplated that motilityof the nematodes is assayed in some methods of the invention.

In some embodiments, the methods first involve identifying anappropriate substance to screen. In certain embodiments, the substancewill be a chalcogenide, reducing agent, or have the structure of FormulaI or Formula IV, or any other compound discussed herein.

It is further contemplated that subsequent screens can be done inorganisms considered higher or more complex than those used inpreliminary or initial screens. Thus, it is contemplated that one ormore cellular respiration factors will be assayed in these otherorganisms to further evaluate a candidate compound. In certainembodiments, subsequent screens involve the use of mice, rats, dogs,etc.

It is contemplated that a number of different organisms or biologicalmatter (other cells or tissues) could be used and a number of differentcellular respiration factors could be assayed in screening methods ofthe invention. In addition, it is contemplated that multiple suchscreens are performed at the same time in some embodiments of theinvention.

It will of course be understood that in order for the substance to beconsidered a candidate active compound (or oxygen antagonist, or stasisinducer or protective metabolic agent, etc.) the substance must not killthe organism or cells in the assay and the effect must be reversible(that is, the characteristic that is altered needs to resume to itslevel before the exposure to the substance).

It is of course understood that any method of treatment can be used inthe context of a preparation of a medicament for the treatment of orprotection against the specified disease or condition. This includes,but is not limited to, the preparation of a medicament for the treatmentof hemorrhagic or hematologic shock, wounds and tissue damage,hyperthermia, hypothermia, neurodegeneration, sepsis, cancer, andtrauma. Moreover, the invention includes, but is not limited to, thepreparation of a medicament for a treatment to prevent death, shock,trauma, organ or tissue rejection, damage from cancer therapy,neurodegeneration, and wound or tissue damage.

As discussed above, organismal stasis is not any of the followingstates: sleep, comatose, death, anesthetized, or grand mal seizure.However, it is contemplated in some embodiments of the invention, thatsuch states are the desired goal of employing methods, compositions andarticles of manufacture of the invention. Any embodiment discussed withrespect to one aspect of the invention applies to other aspects of theinvention as well. Moreover, embodiments may be combined.

Any embodiment involving “exposing” biological matter to an activecompound may also be implemented so that biological matter is providedwith the active compound or administered the active compound. The term“provide” is used according to its ordinary and plain meaning: “tosupply or furnish for use” (Oxford English Dictionary), which, in thecase of patients, may refer to the action performed by a doctor or othermedical personnel who prescribes a particular active compound oradministers it directly to the patient.

The embodiments in the Example section are understood to be embodimentsof the invention that are applicable to all aspects of the invention.

The use of the term “or” in the claims is used to mean “and/or” unlessexplicitly indicated to refer to alternatives only or the alternativesare mutually exclusive, although the disclosure supports a definitionthat refers to only alternatives and “and/or.”

Throughout this application, the term “about” is used to indicate that avalue includes the standard deviation of error for the device or methodbeing employed to determine the value. In any embodiment discussed inthe context of a numerical value used in conjunction with the term“about,” it is specifically contemplated that the term about can beomitted.

Following long-standing patent law, the words “a” and “an,” when used inconjunction with the word “comprising” in the claims or specification,denotes one or more, unless specifically noted.

Other objects, features and advantages of the present invention willbecome apparent from the following detailed description. It should beunderstood, however, that the detailed description and the specificexamples, while indicating specific embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and areincluded to further demonstrate certain aspects of the presentinvention. The invention may be better understood by reference to one ormore of these drawings in combination with the detailed description ofspecific embodiments presented herein.

FIG. 1 Human keratinocytes survive exposure to 100% CO. Cells wereinspected visually using an inverted phase contrast microscope.Quantitation of the number of viable keratinocytes as judged by trypanblue staining, which is an indicator of cell death.

FIG. 2 Discontinuity of survivability in hypoxia. Viabilities toadulthood were assayed following exposure to 24 hours of anoxia (pureN₂), intermediate hypoxia (0.01 kPa O₂, 0.05 kPa O₂ or 0.1 kPa O₂) ormild hypoxia (0.5 kPa O₂) in wild-type embryos. All data points are theresult of at least 3 independent experiments and worms that could not beaccounted for were dropped from the total.

FIG. 3 Carbon monoxide protects against hypoxia. Viabilities toadulthood were assayed following exposure to 24 hours of pure carbonmonoxide, 0.05 kPa O₂₁N₂ or 0.05 kPa O₂/CO in wild-type embryos. Alldata points are the result of at least 3 independent experiments andworms that could not be accounted for were dropped from the total.

FIG. 4A Metabolic rate decreases before body core temperature when miceare exposed to hydrogen sulfide. Exposure of mice to 80 ppm (at 0minutes on the X axis) results in an approximately 3-fold decrease inCO₂ production (black line) in less than five minutes. This precedes thedrop in core temperature of the animal toward the ambient temperature(gray line).

FIG. 4B Temperature of mice exposed to hydrogen sulfide. Each tracerepresents a continuous measurement of core body temperature inindividual mouse exposed to either 80 ppm of H₂S, or to room air.Numbers on the vertical axis are temperature in ° Celsius. On thehorizontal axis, the numbers reflect time in hours. The experiments werecarried out for 6 hours followed by recordings of the recovery. Thebeginning point is at 1:00, and the end of the 6 hr treatment is about7:00.

FIG. 5 Exposure to 80 ppm hydrogen sulfide causes the core bodytemperature of a mouse to approach ambient temperature. Gas was turnedon and temperature decreased starting at time 0:00. Atmosphere switchedback to room air at time 6:00. Triangles indicate the core bodytemperature of the mouse as determined by radiotelemetry. This wasapproximately 39° C. at time 0:00. Diamonds indicate the ambienttemperature which was reduced from 23° C. to 13° C. in the first 3 hoursof the experiment, and then increased again toward 23° C. from hour 6:00stabilizing at around hour 9:00.

FIG. 6 The rate of body core temperature drop is dependent upon theconcentration of hydrogen sulfide given to the mice. All lines representcore body temperature of a single mouse as determined by radiotelemetry.Mice subjected to 20 ppm and 40 ppm H₂S exhibit minor drops in coretemperature. Exposure to 60 ppm induced a substantial drop intemperature beginning at approximately hour 4:00. The mouse exposed to80 ppm exhibited a substantial drop in temperature beginning atapproximately hour 2:00.

FIG. 7 Lowest core body temperature. The lowest core body temperaturerecorded for a mouse exposed to 80 ppm hydrogen sulfide was 10.7° C.Triangles indicate the core body temperature of the mouse as determinedby radiotelemetry which started at approximately 39° C. at time 0.Diamonds indicate the ambient temperature which began at approximately23° C. and was dropped to less than 10° C. by the mid-point of theexperiment, after which it was then increased again toward roomtemperature.

FIG. 8A Endogenous levels of hydrogen sulfide are increased in miceacclimated to warm temperatures. Gray bars (two left bars) indicateendogenous H₂S concentrations of two individual mice acclimated to 4°C.; black bars (two right bars) indicate the endogenous H₂Sconcentrations of two individual mice acclimated to 30° C. Hydrogensulfide concentration determined by GC/MS.

FIG. 8B Effects of Ambient Temperature on Hydrogen Sulfide DependentTemperature prop. The rate of core temperature (expressed in degreesCentigrade) drop due to hydrogen sulfide exposure is dependent on theacclimation temperature. The mice were exposed to the gas at 1:00.Triangles indicate the core body temperature of the mouse, acclimated to12° C., as determined by radiotelemetry. Squares indicate the core bodytemperature of the animal acclimated to 30° C.

FIG. 9 is a block diagram illustrating a respiration gas delivery systemaccording to embodiments of the present invention.

FIG. 10 is a schematic drawing illustrating a respiration gas deliverysystem according to embodiments of the present invention.

FIG. 11 is a schematic drawing illustrating a respiration gas deliverysystem according to further embodiments of the present invention.

FIG. 12 is a flowchart illustrating operations according to embodimentsof the present invention.

FIG. 13 is a schematic drawing illustrating a tissue treatment gasdelivery system according to embodiments of the present invention.

FIG. 14 is a flowchart illustrating operations according to embodimentsof the present invention.

FIG. 15 Metabolic inhibition protects against hypothermia-induced deathin Nematodes. Nematodes exposed to cold temperatures (4° C.) are unableto survive after 24 hours. However, if kept in anoxic conditions duringthe period of hypothermia (and for a 1 hour period before and after), asubstantial proportion of the nematodes survive.

FIG. 16 Short CO₂ pretreatment leads to greatest extension of anoxicsurvival. Adult flies were exposed to 100% CO₂ for the indicated time,the atmosphere was made anoxic by flushing with N₂, and then the tubewas sealed. After 22 h, the tubes were opened to room air. The flieswere allowed to recover for 24 h before scoring viability.

FIG. 17 CO₂ variably enhances anoxic survival. Adult flies were madeanoxic in low-flow experiment, either directly from room air (nopretreatment) or after being exposed to 100% CO₂ for 10 min. After theindicated time, the tubes were opened to room air. The flies wereallowed to recover for 24 h before scoring viability.

FIG. 18 50 ppm H₂S added to CO increases fraction of flies that surviveanoxia. Adult flies were made anoxic in low-flow experiments, eitherdirectly from room air (no pretreatment) or after being exposed to 50ppm H₂S balanced with CO.

FIG. 19 is a schematic diagram of an example system for removing oxygenfrom platelets and a solution in accordance with embodiments of thepresent disclosure.

FIG. 20A-B show the change in core temperature of rats exposed tohydrogen sulfide (A) and mice exposed to carbon dioxide (B).

FIG. 21 Gas Matrix showing stepwise experimental plan to determineconcentration of active compounds.

FIG. 22A-B show negative pressure devices that can be used to deliver oradminister active compounds.

FIG. 23 Survival of Mice in 5% Oxygen. Mice were exposed to either 30minutes of room air before exposure to 5% O₂ (control; black line; n=9)or 10 minutes of room air followed by 20 minutes of 150 ppm H₂S beforeexposure to 5% O₂ (experimental; red line; n=20) and their length ofsurvival measured. Experiments were stopped at 60 minutes and if theanimals were still alive (all of the experimental, none of the controls)they were returned to their cage.

FIG. 24 H₂S Increases Survival at Lethal Oxygen Tensions. Chart showingresults of experiment described in FIG. 23. The x-axis shows the time inminutes that the mice survived in the lower oxygen tensions. The darkbars show when H₂S is absent while the lighter bars show when H₂S ispresent. In the latter groups, mice were exposed to 150 ppm H₂S prior tothe oxygen tension being reduced to between 5% and 2.5%. Survival timeswere measured and was at least 60 minutes in all the H₂S treated groups.

FIG. 25 Metabolic Rate of a Mouse in 5% Oxygen. A mouse was exposed to10 minutes of room air followed by 20 minutes of 150 ppm H₂S prior toexposure to 5% O₂. Metabolic rate measured by CO₂ output. Pre-exposureCO₂ output was approximately 2500 ppm, after 20 minutes of H₂S thenmetabolic rate was down approximately 2-fold and after several hours ofexposure to 5% O₂ the CO₂ output had dropped approximately 50-fold frompre-exposure levels to approximately 50 ppm. At hour 6 the mouse wasreturned to room air and allowed to recover. This data is from one ofthe mice included in FIG. 23 (experimental group).

FIG. 26 Mouse Exposed to 100 ppb H₂Se. Chart shows exposure to H₂Se inminutes (x-axis) with drop in core body temperature (temperature incelsius shown on right plotted with line showing gradual decrease) andwith decrease in respiration (ppm CO₂ shown on left plotted with jaggedline showing decrease).

FIG. 27 Mouse Exposed to 10 ppb H₂Se. Chart shows exposure to H₂Se inminutes (x-axis) with drop in core body temperature (temperature incelsius shown on right plotted with line showing gradual decrease) andwith decrease in respiration (ppm CO₂ shown on left plotted with jaggedline showing decrease with lowest point at five minute exposure).

FIG. 28 H₂S Pre-treatment Enhances Survival of Mice Under HypoxicConditions. Mice were exposed to either 30 minutes of room air (No PT)or 10 minutes of room air followed by 20 minutes of 150 ppm H₂S (PT)before exposure to 5% O₂ (5%), 4% O₂ (4%), 5% O₂ for 1 hr followed by 4%O₂ (4%+1 hr 5%), or 5% O₂ for 1 hr followed by 3% O₂ (3%+1 hr 5%), andtheir length of survival measured. Experiments were stopped at 60minutes and if the animals still alive were returned to their cage.

FIG. 29 CO₂ Production During Transition to Lethal Hypoxia. Changes inCO₂ production upon transition to either 5% O₂ or 4% O₂ were measured inmice exposed to either room air for 30 minutes (No PT) or room air for10 minutes followed by 150 ppm H₂S for 20 minutes (PT). In addition, thechange in CO₂ production upon step-wise transition to 5% O₂ for 1 hrfollowed by 4% O₂ was measured. The percent change in CO₂ production isplotted with standard error indicated.

FIG. 30 Human keratinocytes survive exposure to 100% carbon monoxide(CO). Cells were inspected visually using an inverted phase contrastmicroscope. Quantitation of the number of viable keratinocytes as judgedby trypan blue staining, which is an indicator of cell death.

FIG. 31 Chronic exposure to low levels of H₂S leads to heat resistancein C. elegans. Nematodes adapted to environments containingapproximately 50 ppm H₂S in house air, were significantly more resistantto lethal effects of elevating the ambient temperature to 35 degrees C.compared to siblings raised in house air alone.

FIG. 32 Chronic exposure to low levels of H₂S increases lifespan in C.elegans. Nematodes that were adapted to environments containingapproximately 50 ppm H₂S in house air had longer lifespan compared tountreated controls.

FIG. 33 Examples of transient core temperature drop in Sprague-Dawleyrats. Core temperature measurements from rats exposed to 0.03% hydrogensulfide mixed with room air (gray/dotted line) or 15% carbon dioxide/8%oxygen/77% helium (dark/solid line). In this experiment the temperatureof the environmental chamber was 10° C. during the treatment phase. Thetemperature of the environmental chamber was restored to roomtemperature (22° C.) when the gas was returned to room air. In each casethis was the point (approximately 2 hours for the dark/solid line andapproximately 7.4 hours for the gray/dotted line) where the coretemperature began to rise.

FIG. 34 Mouse core body temperature during exposure to 1.2 ppm ofhydrogen selenide for 2 hours and 10 minutes in room air at 5° C.ambient temperature.

FIG. 35 Rat core body temperature during exposure to room air in anenvironmental chamber at an ambient temperature of 10° C. Dark linedescribes the core temperature of the rat. The gray line describes theambient temperature.

FIG. 36 Core body temperature of a rat exposed to 80% helium 20% oxygenat an ambient temperature of 7° C. Time is described on the X axis inhours. The total time of exposure was approximately 5 hours (from 9:15AM to 2:15 PM). No significant drop in core body temperature was seen.

FIG. 37 Core body temperature of a rat during exposure to 15% carbondioxide, 20% oxygen, and 75% Helium at an ambient temperature of 7° C.The time of exposure was approximately 2 hours. The rat was exposed toroom air beginning at the point where the temperature begins to rise(shortly after the point labeled 38512.6). During the period when therat was exposed to room air the temperature of the environment wasrestored to room temperature.

FIG. 38. Core temperature of a rat exposed to 15% carbon dioxide, 8%oxygen, and 77% Helium at an ambient temperature of 7° C. The exposuretime was approximately 4 hours. The gray line describes the ambienttemperature. The dark line describes the core temperature. At the pointwhere the ambient and cores temperatures rise is the point where the gaswas switched to room air.

FIG. 39. Core temperature of a dog exposed to carbondioxide/helium/oxygen. Dotted lines are when the gas went on(approximately 24 minutes) and off (approximately 55 minutes). FIG. 40.Core temperature of a dog exposured to increasing concentrations ofcarbon dioxide. Dotted lines indicate when changes in the gas were made.At approximately 63 minutes the gas was changed from room air to 9%carbon dioxide in room air. At approximately 85 minutes the atmospherewas changed from 9% carbon dioxide in room air to 12% carbon dioxide inroom air. At approximately 115 minutes the atmosphere was changed from12% carbon dioxide in room air to 15% carbon dioxide in room air. Theexperiment ended at approximately 135 minutes.

FIG. 41 Apparatus employed in screening methods.

FIG. 42 Oxygen consumption (gray bars) and carbon dioxide production(black bars) of animals exposed to hydrogen sulfide for 4 hours per dayfor at least 1 week and for control animals that were exposed to thesame conditions lacking hydrogen sulfide.

FIG. 43 Respiratory quotient for animals exposed to hydrogen sulfide for4 hours per day for at least 1 week (H₂S 2900 and H₂S 2865) and forcontrol animals (2893 and 2894) that were exposed to the same conditionslacking hydrogen sulfide.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS I. Stasis

In “stasis” or “suspended animation,” a cell, tissue or organ, ororganism (collectively referred to as “biological material”) is living,but cellular functions necessary for cell division, developmentalprogression, and/or metabolic state are slowed or even stopped. Thisstate is desirable in a number of contexts. Stasis can be used as amethod of preservation by itself, or it may be induced as part of acryopreservation regimen. Biological materials may be preserved forresearch use, for transportation, for transplantation, for therapeutictreatment (such as ex vivo therapy), and to prevent the onset of trauma,for example. Stasis with respect to entire organisms has similar uses.For instance, transportation of organisms could be facilitated if theyhad entered stasis. This might reduce physical and physiological damageto the organism by reducing or eliminating stress or physical injury.These embodiments are discussed in further detail below. Stasis may bebeneficial by decreasing the need of the biological material for oxygenand, therefore, bloodflow. It may extend the period of time thatbiological material can be isolated from a life-sustaining environmentand exposed to a death-inducing environment.

While recovery has been reported from accidental hypothermia for arelatively prolonged period of time (Gilbert et al., 2000), there hasbeen recent interest in intentionally inducing suspended animation inorganisms. (The discussion of any reference is not to be construed as anadmission that the reference constitutes prior art. In fact, somereferences discussed herein would not be prior art with respect to thepriority applications.) Controlled hyperthermia has been explored, aswell as the administration of a cold flush of a solution into the aorta(Tisherman, 2004), induction of cardiac arrest (Behringer et al., 2003),or nitric oxide-induced suspended animation (Teodoro et al., 2004).

An organism in stasis is distinguishable from an organism under generalanesthesia. For example, an organism in mild stasis (between about 2-and about 5-fold decrease in cellular respiration) that is exposed toroom air will begin to shiver, while an organism under anesthesia willnot. Also, an organism in mild stasis is anticipated to respond to a toesqueeze, while an organism under anesthesia usually does not.Consequently, stasis is not the same thing as being under anesthesia asit is commonly practiced.

CO₂ production is a direct marker of cellular respiration related tometabolism of an organism. This may be distinguished from “CO₂evolution,” which refers to the amount of CO₂ blown out of the lungs.Certain active compounds, e.g., hydrogen sulfide, can inhibit carbonicanhydrase activity in the lungs, this inhibiting conversion of carbonateto CO₂ and its liberation from the pulmonary blood, thereby exhibitingan associated reduction in CO₂ evolution, without a correspondingdecrease in cellular CO₂ production.

The present invention is based on the observation that certain types ofcompounds effectively induce reversible stasis in biological matter.Other patent applications discuss induction of stasis, including thefollowing: U.S. patent application Ser. Nos. 10/971,576, 10/972,063, and10/971,575; U.S. patent application Ser. No. 10/971,576; U.S. patentapplication Ser. No. 10/972,063; and U.S. patent application Ser. No.10/971,575, all of which are hereby incorporated by reference.

A. Thermoregulation

Stasis in a warm-blooded animal will affect thermoregulation.Thermoregulation is a characteristic of so-called “warm-blooded”animals, which permits the organism to maintain a relatively constantcore body temperature even when exposed to significantly altered (coldor hot) environmental temperatures. The ability to controlthermoregulation by induction of stasis is one aspect of the invention,and permits uses similar to those discussed above.

Thermal regulation may be facilitated by placing of organisms, limbs orisolated organs or tissues into chambers/devices, the temperature ofwhich can be controlled. For example, warm rooms or chamber-like devicessimilar to hyperbaric chambers may encompass an entire organism and beconnected to thermo-regulatory apparti. Smaller devices such asblankets, sleeves, cuffs or gloves (e.g., CORE CONTROL cooling system byAVAcore Technologies, Palo Alto, Calif., U.S. Pat. No. 6,602,277) arealso contemplated. Such chambers/devices may be used both to increase orreduce ambient temperatures.

B. Biological Matter

Biological matter contemplated for use with the present inventioninclude material derived from invertebrates and vertebrates, includingmammals; biological materials includes organisms. In addition to humans,the invention can be employed with respect to mammals of veterinary oragricultural importance including those from the following classes:canine, feline, equine, bovine, ovine, murine, porcine, caprine, rodent,lagomorph, lupine, and ursine. The invention also extends to fish andbirds. Other examples are disclosed below.

Moreover, the type of biological matter varies. It can be cells, tissuesand organs, as well as organisms for which different compositions,methods, and apparatuses have relevance. The nonprovisional U.S. patentapplication Ser. Nos. 10/971,576, 10/972,063, and 10/971,575 are herebyincorporated by reference in their entireties.

In some embodiments, the biological material is or comprises cells. Itis contemplated that the cell may be any oxygen-utilizing cell. The cellmay be eukaryotic or prokaryotic. In certain embodiments, the cell iseukaryotic. More particularly, in some embodiments, the cell is amammalian cell. Mammalian cells contemplated for use with the inventioninclude, but are not limited to those that are from a: human, monkey,mouse, rat, rabbit, hamster, goat, pig, dog, cat, ferret, cow, sheep,and horse.

Moreover, cells of the invention may be diploid, but in some cases, thecells are haploid (sex cells). Additionally, cells may be polyploid,aneuploid, or anucleate. The cell can be from a particular tissue ororgan, such as one from the group consisting of: heart, lung, kidney,liver, bone marrow, pancreas, skin, bone, vein, artery, cornea, blood,small intestine, large intestine, brain, spinal cord, smooth muscle,skeletal muscle, ovary, testis, uterus, and umbilical cord. Moreover,the cell can also be characterized as one of the following cell types:platelet, myelocyte, erythrocyte, lymphocyte, adipocyte, fibroblast,epithelial cell, endothelial cell, smooth muscle cell, skeletal musclecell, endocrine cell, glial cell, neuron, secretory cell, barrierfunction cell, contractile cell, absorptive cell, mucosal cell, limbuscell (from cornea), stem cell (totipotent, pluripotent or multipotent),unfertilized or fertilized oocyte, or sperm.

1. Different Sources

The following are examples of sources from which biological matter maybe obtained. Embodiments of the invention include, but are not limitedto, these examples.

a. Mammals

In certain aspects of the invention, the mammal is of the OrderMonotremata, Marsupialia, Insectivora, Macroscelidia, Dermoptera,Chiroptera, Scandentia, Primates, Xenarthra, Pholidota, Tubulidentata,Lagomorpha, Rodentia, Cetacea, Carnivora, Proboscidea, Hyracoidea,Sirenia, Perissodactyla, or Artiodactyla.

Examples of Monotremata include the Families Tachyglossidae (e.g.,Echidnas) and Ornithorhynchidae (e.g., Platypus). Examples ofMarsupialia include the Families Didelphidae (e.g., Opossums),Microbiotheriidae (e.g., Monito del Monte), Caenolestidae (e.g., RatOppossums), Dasyuridae (e.g., Marsupial mice), Myrmecobiidae (e.g.,Numbat), Thylacimidae (e.g., Thylacine), Peramelidae (e.g., Bandicoots),Thylacomyidae (e.g., Rabbit Bandicoots), Notoryctidae (e.g., MarsupialMoles), Phalangeridae (e.g., Cuscuses), Petauridae (e.g., Ringtails,Gliders), Burramyidae (e.g., Pygmy Possums), Macropodidae (e.g.,Kangaroos, Wallabies), Tarsipedidae (e.g., Honey Possum), Vombatidae(e.g., Wombats), and Phascolarctidae (e.g., Koalas).

Insectivora includes, for example, the Families Solenodontidae (e.g.,Solenodons), Tenrecidae (e.g., Tenrecs, Otter Shrews), Chrysochloridae(e.g., Golden Moles), Erinaceidae (e.g., Hedgehogs, Moonrats), Soricidae(e.g., Shrews), and Talpidae (e.g., Moles, Desmans). The OrderMacroscelidia includes the Family Macroscelidia (e.g., Elephant Shrews).The Order Scandentia includes Tupaiidae (e.g., Tree Shrews). The OrderDermoptera includes the Family Cynocephalidea (e.g., Flying Lemurs).Chiroptera includes the Families Pteropodidae (e.g., Fruit Bats, FlyingFoxes), Rhinopomatidae (e.g., Mouse-Tailed Bats), Craseonycteridae(e.g., Hog-Nosed or Bumblebee Bat), Emballonuridae (e.g., Sheath-TailedBats), Nycteridae (e.g., Slit-Faced Bats), Megadermatidae (e.g., FalseVampire Bats), Rhinolophidae (e.g., Horshoe Bats), Noctilionidae (e.g.,Bulldog Bats, Fisherman Bats), Mormoopidae, Phyllostomidae (e.g., NewWorld Leaf-Nosed Bats), Natalidae, Furipteridae, Thyropteridae,Myzapodidae, Vespertilionidae (e.g., Common Bats), Mystacimidae (e.g.,Short-Tailed Bats), and Molossjdae (e.g., Free-Tailed Bats).

The Order Primates includes the Families Lemuridae (e.g., Lemurs),Chemogaleidae (e.g., Mouse Lemurs), Indriidae (e.g., Indri, WoollyLemur), Daubentoniidae (e.g., Aye-Aye), Lorisidae (e.g., Lorises,Bushbabies, Galagos), Tarsiidae (e.g., Tarsiers), Cebidae (e.g., NewWorld Monkeys, Marmosets, Tamarins), Hylobatidae (e.g., Gibbons),Pongidae (e.g., Apes), and Homimidae (e.g., Man).

Examples of Xenarthra include Myrmecophagidae (e.g., Anteaters),Bradypodidae (e.g., Three-Toed Sloths), Megalonychidae (e.g., Two-ToedSloths), and Dasypodidae (e.g., Armadillos). Examples of Pholidotainclude Manidae (e.g., Pangolins). Examples of Tubulidentata includeOrycteropodidae (e.g., Aardvarks). Examples of Lagomorpha includeOchotonidae (e.g., Pikas) and Leporidae (e.g., Hares and Rabbits).

The Order Rodentia includes the Families Aplodontidae (e.g., MountainBeavers), Sciuridae (e.g., Squirrels, Marmots, Chipmunks), Geomyidae(e.g., Pocket Gophers), Heteromyidae (e.g., Pocket Mice, Kangaroo Rats),Castoridae (e.g., Beaver), Anomaluridae (e.g., Scaly-Tailed Squirrels),Pedetidae (e.g., Springhare), Muridae (e.g., Rats and Mice), Gliridae(e.g., Dormice), Selevimidae (e.g., Desert Dormouse), Zapodidae (e.g.,Jumping Mice), Dipodidae (e.g., Jerboas), Hystricidae (e.g., Old WorldPorcupines), Erethizontidae (e.g., New World Porcupines), Caviidae(e.g., Guinea Pigs, Maras), Hydrochaeridae (e.g., Capybara), Dinomyidae(e.g., Pacarana), Agoutidae (e.g., Pacas), Dasyproctidae (e.g.,Agoutis), Chinchillidae (e.g., Chinchillas, Viscachas), Capromyidae(e.g., Hutias), Myocastoridae (e.g., Nutria), Ctenomyidae (e.g.,Tuco-Tucos), Octodontidae (e.g., Octodonts, Degus), Abrocomidae (e.g.,Chichilla Rats), Echimyidae (e.g., Spiny Rats), Thryonomyidae (e.g.,Cane Rats), Petromyidae (e.g., African Rock Rat), Bathyergidae (e.g.,Mole Rat), and Ctenodactylidae (e.g., Gundis).

The Order Cetacea includes the Families Imidae (e.g., Amazon Popoise),Lipotidae, Platanistidae, Pontoporiidae, Ziphiidae (e.g., BeakedWhales), Physeteridae (e.g., Sperm Whales), Monodontidae (e.g., BelugaWhale, Narwhal), Delphimidae (e.g., Marine Dolphins, Killer Whales),Phocoenidae (e.g., Porpoises), Balaenopteridae (e.g., Rorquals),Balaenidae (e.g., Right Whales), and Eschrichtiidae (e.g., Gray Whales).

The Order Camivora includes the Families Canidae (e.g., Dogs, Foxes,Wolves, Jackals, Coyotes), Ursidae (e.g., Bears), Procyonidae (e.g.,Raccoons, Coatis, Kinkajous, Lesser Pandas), Ailuropodidae (e.g., GiantPandas), Mustelidae (e.g., Weasels, Skunks, Badgers, Otters), Viverridae(e.g., Civets, Genets), Herpestidae (e.g., Mongooses), Protelidae (e.g.,Aardwolf), Hyaenidae (e.g., Hyenas), Felidae (e.g., Cats), Otariidae(e.g., Eared Seals, Sea Lions), Odobenidae (e.g., Walrus), and Phocidae(e.g., Earless Seals).

The Order Proboscidea includes the Family Elephantidae (e.g.,Elephants). Hyracoidea includes the Family Procaviidae (e.g., Hyraxes).Sirenia includes the Families Dugongidae (e.g., Dugong) and Trichechidae(e.g., Manatees). The Order Perissodactyla includes the Families Equidae(e.g., Horses, Assess, Zebras), Tapiridae (e.g., Tapirs), andRhinocerotidae (e.g., Rhinoceroses). The Order Artiodactyla includes theFamilies Suidae (e.g., Pigs, Babirusa), Tayassuidae (e.g., Peccaries),Hippopotamidae (e.g., Hippopotamuses), Camelidae (e.g., Camels, Llamas,Vicunas), Tragulidae (e.g., Chevrotains), Moschidae (e.g., Musk Deer),Cervidae (e.g., Deer, Elk, Moose), Giraffidae (e.g., Giraffe, Okapi),Antilocapridae (e.g., Pronghom), and Bovidae (e.g., Cattle, Sheep,Antelope, Goats).

b. Reptiles

In certain embodiments, the biological material is a reptile or isderived from a reptile. The reptile may be of the Order Chelonia,Pleurodira, Squamata, Rhynchocephalia, or Crocodylia. A reptile of theOrder Chelonia may be, for example, a Carettochelyidae, Chelydridae(e.g., Snapping Turtles), Cheloniidae (e.g., Loggerhead Turtles, GreenTurtles), Dermatemydidae (e.g., Leatherback Turtles), Emydidae (e.g.,Paitned Turtles, Pond Sliders, Pond Turtles, Snail-Eating Turtles, BoxTurtles), Kinosternidae (e.g., Stinkpot Turtles), Saurotypidae,Testudinidae (e.g., Galapagos Tortoises, Desert Tortoises, AldabraTurtles, Spu-Thighed Tortoises, Hermann's Tortoise), Trionychidae (e.g.,Chinese Softshells, Spiny Softshells), or a Platysternidae. A reptile ofthe Order Pleurodira may be, for example, a Chelidae (e.g., Snake-NeckedTurtles) or Pelomedusidae (e.g., Helmeted Turtles).

A reptile of the Order Squamata may be, for example, an Agamidae (e.g.,Rainbow Lizards, Bearded Dragons, Indian Bloodsuckers, Spiny-TailedLizards), Chamaeleontdidae (e.g., Chameleons), Iguanidae (e.g., Anoles,Basilisks, Collared Lizards, Iguanas, Horned Lizards, Chuckwallas,Sagebrush Lizards, Side-Blotched Lizards), Gekkonidae (e.g., Geckos),Pygopodidae, Teiidae (e.g., Race Runners, Tegus), Lacertidae (e.g., SandLizards, Ocellated Lizards, Viviparous Lizards, Wall Lizards,Long-Tailed Lizards), Xantuslidae, Scincidae (e.g., Skinks), Cordylidae(e.g., Sungazers), Dibamidae, Xenosauridae, Anguidae (e.g., Slow Worm,Alligator Lizards, Sheltopusik, Glass Lizards), Helodermatidae (e.g.,Gila Monster), Lanthanotidae, Varanidae (e.g., Monitors),Leptotyphlopidae, Typhlopidae, Anomalepididae, Aniliidae (e.g., PipeSnakes), Uropeitidae, Xenopeltidae, Boidae (e.g., Boas, Anacondas, RockPythons), Acrochordidae (e.g., Wart Snakes), Colubridae (e.g., MangroveSnakes, Whip Snakes, Smooth Snakes, Egg-Eating Snakes, Boomslangs, RatSnakes, Aesculapian Snakes, Four-Lined Snakes, Oriental Beauty Snake,Tentacled Snakes, Hognose Snakes, Kingsnakes, Montpelier Snakes, GrassSnakes, Water Snakes, Garter Snakes, Twig Snakes, Keelback Snakes),Elapidae (e.g., Death Adders, Kraits, Mambas, Coral Snakes, Cobras,Copperhead, Puff Adder), Viperidae (e.g., Vipers, Right Adders,Rattlesnakes, Massasaugas, Adder), Hydrophiidae (e.g., Sea Brait),Amphisbaenidae (e.g., Worm Lizard), Bipedidae, or a Trogonophidae (e.g.,Burrowing Lizard).

A reptile of the Order Rhynchocephalia may be, for example, aSphenodontidae (e.g., Tuataras). A reptile of the Order Crocodylia maybe, for example, an Alligatoridae (e.g., Alligators, Caiman),Crocodylidae (e.g., Crocodiles), or a Gavialidae (e.g., Gharials).

c. Amphibians

The biological material of the present invention may be an amphibian ormay be derived from an amphibian. The amphibian may be, for example, afrog or a toad. The frog or toad may be, for example, an Arthroleptidae(e.g., screeching frogs), Ascaphidae (e.g., tailed frogs),Brachycephalidae (e.g., gold frogs and shield toads), Bufonidae (e.g.,true toads), Centrolenidae (e.g., glass frogs and leaf frogs),Dendrobatidae (e.g., poison-dart frogs), Discoglossidae (e.g.,fire-bellied toads), Heleophrynidae (e.g., ghost frogs), Hemisotidae(e.g., shovel-nosed frogs), Hylidae (e.g., New World tree frogs),Hyperoliidae (e.g., African tree frogs), Leiopelmatidae (e.g., NewZealand frogs), Leptodactylidae (e.g., neotropical frogs), Megophryidae(e.g., South Asian frogs), Microhylidae (e.g., microhylid frogs),Myobatrachidae (e.g., Australian frogs), Pelobatidae (e.g., spadefoottoads), Pelodytidae (e.g., parsley frogs), Pipidae (e.g., tonguelessfrogs), Pseudidae (e.g., paradox frogs), Ranidae (e.g., riparian frogsand true frogs), Rhacophoridae (e.g., Old World tree frogs),Rhinodermatidae (e.g., Darwin's frogs), Rhinophrynidae (e.g., burrowingtoad), Sooglossidae (e.g., Seychelle frogs), Caudata (e.g.,salamanders), or a Gymnophiona (e.g., caecilians).

The amphibian may be a salamander. The salamander may be, for example,an Ambystomatidae (e.g., mole salamanders), Amphiumidae (e.g.,amphiumas), Cryptobranchidae (e.g., giant salamanders and hellbenders),Dicamptodontidae (e.g., Pacific giant salamanders), Hynobiidae (e.g.,Asiatic salamanders), Plethodontidae (e.g., lungless salamanders),Proteidae (e.g., mudpuppies and waterdogs), Rhyacotritonidae (e.g.,torrent salamanders), Salamandridae (e.g., newts and salamanders), or aSirenidae (e.g., sirens). Alternatively, the amphibian may be aCaecilian. The Caecilian may be, for example, a Caeciliidae (e.g.,caecilians), Ichthyophiidae (e.g., Asiatic tailed caecilians),Rhinatrematidae (e.g., neotropical tailed caecilians), Scolecomorphidae(e.g., African caecilians), Typhlonectidae (e.g., aquatic caecilians),or an Uraeotyphlidae (e.g., Indian caecilians).

d. Birds

The biological material of the present invention may be a bird or may bederived from a bird. The bird may be, for example, an Anseriforme (e.g.,waterfowl), Apodiforme (e.g., hummingbirds and swifts), Caprimulgiforme(e.g., nightbirds), Charadriiforme (e.g., shorebirds), Ciconiiforme(e.g., storks), Colilforme (e.g., mousebirds), Columbiforme (e.g., dovesand pigeons), Coraciiforme (e.g., kingfishers), Craciforme (e.g.,chacalacas, curassows, guans, megapodes), Cuculiforme (e.g., cuckoos,hoatzin, turacos), Falconiforme (e.g., diurnal birds of prey),Galliforme (e.g., chicken-like birds), Gaviiforme (e.g., loons),Gruiforme (e.g., coots, cranes, rails), Passeriforme (e.g., perchingbirds), Pelecaniforme (e.g., pelicans), Phoenicopteriforme (e.g.,flamingos), Piciforme (e.g., woodpeckers), Podicipediforme (e.g.,grebes), Procellariiforme (e.g., tube-nosed seabirds), Psittaciforme(e.g., parrots), Sphenisciforme (e.g., penguins), Strigiforme (e.g.,owls), Struthioniforme (e.g., cassowaires, emus, kiwis, ostriches,rheas), Tinamiforme (e.g., tinamous), Trogoniforme (e.g., trogons), or aTurniciforme (e.g., buttonquail).

e. Fish

The biological material of the present invention may be a fish or may bederived from a fish. The fish may be, for example, an Acipenseriforme(e.g., paddlefishes, spoonfishes, and sturgeons), Polypteriforme (e.g.,bichirs, birchers, lobed-finned pike, and reed fishes), Atheriniforme(e.g., rainbow fishes and silversides), Beloniforme (e.g., halfbeeks andneedlefishes), Beryciforme, Channiforme, Cyprinodontiforme (e.g.,killifishes), Dactylopteriforme (e.g., flying gurnards),Gasterosteiforme (e.g., pipefishes and sticklebacks), Mugiliforme (e.g.,mullets), Pegasiforme (e.g., dragonfishes and sea moths), Perciforme(e.g., perch-like fishes), Pleuronectiforme (e.g., flatfishes,flounders, and soles), Scorpaeniforme (e.g., scorpion fishes andsculpins), Stephanoberyciforme, Synbranchiforme (e.g., swamp eels),Tetraodontiforme (e.g., cowfishes, filefishes, leatherjackets, puffers,triggerfishes, and trunkfishes), Zeiforme (e.g., boarfishes, dories, andjohn dories), Atherinomorpha, Clupeiforme (e.g., anchovies andherrings), Aulopiforme, Albuliforme, Anguilliforme (e.g., eels),Elopiforme (e.g., tarpons), Notacanthiformes (e.g., spiny eels andtapirfishes), Saccopharyngiformes, Lampridiforme (e.g., opahs andribbonfishes), Characiforme (e.g., leporins and piranhas), Cypriniforme(e.g., minnows, suckers, zebra fish), Gonorhynchiforme (e.g., milkfishand shellears), Gymnotiforme, Siluriforme (e.g., catfishes),Aphredoderiforme (e.g., cavefishes and pirate perches),Batrachoidiforme, Gadiforme (e.g., cods and hakes), Gobiesociforme,Lophiiforme (e.g., anglerfishes), Ophidiiforme, Percopsiforme (e.g.,trout-perches), Polymixiiforme (e.g., beardfishes), Cetomimiforme,Ctenotlirissiforme, Esociforme (e.g., mudminnows and pikes), Osmeriforme(e.g., Argentines and smelts), Salmoniforme (e.g., salmons),Myctophiforme (e.g., Latern Fishes), Ateleopodiforme, Stomiiforme,Amiiforme (e.g., bowfins), Semionotiforme (e.g., gars), Syngnathiforme(e.g., pipefishes and seahorses), Ceratodontiforme (e.g., Australianlungfishes), Lepidosireniforme (e.g., South American lungfishes andAfrican lungfishes), or a Coelacanthiforme (e.g., coelacanths).

f. Invertebrates

The biological material maybe an invertebrate or derived from aninvertebrate. The invertebrate may be, for example, a Porifera (e.g.,sponges), Cnidaria (e.g., jellyfish, hydras, sea anemones, Portugueseman-of-wars, and corals), Platyhelminthe (e.g., flatworms, includingplanaria, flukes, and tapeworms), Nematoda (e.g., roundworms, includingrotifers and nematodes), Mollusca (e.g., mollusks, snails, slugs,octopuses, squids), Annelida (e.g., segmented worms, includingearthworms, leeches, and marine worms), Echinodermata (e.g., sea stars,sea cucumbers, sand dollars, sea urchins), Phoronida (e.g., HorseshoeWorms), Tardigrada (e.g., Water Bears), Acanthocephala (e.g., SpinyHeaded Worms), Ctenophora (e.g., Comb Jellies), or an Arthropod (e.g.,arachnids, crustaceans, millipedes, centipedes, insects).

An Arthropod may be, for example, a Coleoptera (e.g., beetles), Diptera(e.g., true flies), Hymenoptera(e.g., ants, bees, wasps),Lepidoptera(e.g., butterflies, moths), Mecoptera (e.g., scorpion flies),Megaloptera, Neuroptera (e.g., lacewings and relatives),Siphonaptera(e.g., fleas), Strepsiptera (e.g., parasitic insects andtwisted-winged parasites), Trichoptera (e.g., caddisflies), Anoplura(e.g., sucking lice), Hemiptera (e.g., true bugs and their relatives),Mallophaga (e.g., biting lice), Psocoptera (e.g., psocids), Thysanoptera(e.g., thrips), Orthoptera (e.g., grasshoppers, locusts),Dermaptera(e.g., earwigs), Dictyoptera, Embioptera (e.g., webspinners),Grylloblattodea, Mantophasmatodea (e.g., gladiators), Plecoptera (e.g.,stoneflies), Zoraptera (e.g., zorapterans), Ephemeroptera (e.g.,mayflies), Odonata (e.g., dragonflies and damselflies), Phasmatoptera(e.g., walkingsticks), Thysanura (e.g., bristletails), Archaeognatha,Collembola (e.g., snow flies and springtails), Chilopoda (e.g.,centipedes), Diplopoda (e.g., millipedes), Pauropoda (e.g., pauropods,pauropodans, and progoneates), Symphyla (e.g., pseudocentipedes andsymphylans), Malacostraca (e.g., crabs, krill, pill bugs, shrimp),Maxillopoda, Branchiopoda (e.g., branchiopods), Cephalocarida, Ostracoda(e.g., ostracods), Remipedia, Branchiura, Cirripedia (e.g., barnacles),Arachnida (e.g., arachnids, including amblypygids, spiders, daddylonglegs, harvestmen, microscorpions, book scorpions, false scorpions,pseudoscorpions, scorpions, solpugids, sun spiders, and uropygids),Merostomata (e.g., horseshoe crabs), or a Pycnogonida (e.g., seaspiders).

g. Fungi

The biological material of the present invention may be a fungi or maybe derived from a fungi. The fungi may be, for example, an Ascomycota(sac fungi), Basidiomycota (club fungi), Chytridiomycota (chytrids),Deuteromycota, or a Zygomycota. The fungi may be a Rhizopus, Pilobolus,Arthrobotrys, Aspergillus, Allomyces, Chytridium, Agaricus, Amanita,Cortinarius, Neurospora, Morchella, Saccharomyces, Pichia, Candida,Schizosaccharomyces, or Ergot. In particular embodiments the fungi maybe Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candidaalbicans, or Pichia pastoris.

h. Plants

The biological material of the present invention may be a plant or maybe derived from a plant. The plant may be a Bryophyte (e.g., mosses,liverworts, hornworts), Lycophyte (e.g., club mosses, ground pine),Sphenophyte (e.g., horsetails), Pterophyte (e.g., ferns), Cycadophyte(e.g., cycads), Gnetophyte (e.g., gnetum, ephedra, welwitschia),Coniferophyte (e.g., conifers), Ginkophyte (e.g., ginko), or Anthophyte(e.g., flowering plants). The Anthophyte may be a monocot or a dicot.Non-limiting examples of monocotyledonous plants include wheat, maize,rye, rice, turfgrass, sorghum, millet, sugarcane, lily, iris, agave,aloe, orchids, bromeliads, and palms. Non-limiting examples ofdicotyledonous plants include tobacco, tomato, potato, soybean,sunflower, alfalfa, canola, rose, Arabidopsis, coffee, citrus fruits,beans, alfalfa, and cotton.

i. Protists

The biological material of the present invention may be a Protist or maybe derived from a Protist. The Protist may be a Rhodophyte (e.g., redalgea), Phaeophyte (e.g., brown algea, kelp), Chlorophyte (e.g., greenalgea). Euglenophyte (e.g., euglenoids) Myxomycot (e.g., slime molds),Oomycot (e.g., water molds, downy mildews, potato blight), orBacillariophyte (e.g., diatoms).

j. Prokaryotes

In certain aspects of the invention, the biological material is aprokaryote or is derived from a prokaryote. In certain embodiments theprokaryote is an Archaea (archaebacteria). The archaebacteria may be,for example, a Crenarchaeota, Euryarchaeota, Korarchaeota orNanoarchaeota. In certain aspects the Euryarchaeota is a Halobacteria,Methanobacteria, Methanococci, Methanomicrobia, Methanosarcinae,Methanopyri, Archeoglobi, Thermoplasmata, or a Thermococci. Specific,non-limiting examples of archaebacteria include: Aeropyrum pernix,Methanococcus jannaschii, Halobacterium marismortui, and Thermoplasmaacidophilum.

In certain embodiments the prokaryote is an Eubacteria. The Eubacteriamay be, for example, an Actinobacteria, Aquificae, Bacteroidetes, Greensulfur bacteria, Chlamydiae, Verrucomicrobia, Chloroflexi,Chrysiogenetes, Cyanobacteria, Deferribacteres, Deinococcus-Thermus,Dictyoglomi, Fibrobacteres/Acidobacteria, Firmicutes, Fusobacteria,Gemmatimonadetes, Nitrospirae, Omnibacteria, Planctomycetes,Proteobacteria, Spirochaetes, Thermodesulfobacteria, or Thermotogae.Non-limiting examples of Actinobacteria include bacteria of the generaActinomyces, Arthrobacter, Corynebacterium, Frankia, Micrococcus,Micromonospora, Mycobacterium, Propionibacterium, and Streptomyces.Specific examples of Actinobacteria include Mycobacterium leprae,Mycobacterium tuberculosis, Mycobacterium avium, Corynebacteriumglutamicum, Propionibacterium acnes, and Rhodococcus equi.

Non-limiting examples of Aquificae include bacteria of the generaAquifex, Hydrogenivirga, Hydrogenobacter, Hydrogenobaculum,Thermocrinis, Hydrogenothermus, Persephonella, Sulfurihydrogenibium,Balnearium, Desulfurobacterium, and Thermovibrio. Non-limiting examplesof Firmicutes include bacteria of the genera Bacilli, Clostridia, andMolecutes. Specific examples of Fimmicutes include: Listeria innocua,Listeria monocytogenes, Bacillus subtilis, Bacillus anthracis, Bacillusthuringiensis, Staphylococcus aureus, Clostridium acetobutylicum,Clostridium difficile, Clostridium perfringens, Mycoplasma genitalium,Mycoplasma pneumoniae, Mycoplasma pulmonis, Streptococcus pneumoniae,Streptococcus pyogenes, Streptococcus mutans, Lactococcus lactis, andEnterococcus faecalis.

Non-limiting examples of Chlamydiae/Verrucomicrobia include bacteriasuch as Chlamnydia trachomatis, Chlamydia pneumoniae, I Chlamydiapsittaci. Non-limiting examples of Deinococcus-Thermus include bacteriaof the genera Deinococcus and Thermus.

Proteobacteria are gram-negative bacteria. Non-limiting examples ofProteobacteria include bacteria of the genera Escherichia, Salmonella,Vibrio, Rickettsia, Agrobacterium, Brucella, Rhizobium, Neisseria,Bordetella, Burkholderi, Buchnera, Yersinia, Klebsiella, Proteus,Shigella, Haemophilus, Pasteurella, Actinobacillus, Legionella,Mannheimia, Coxiella, Aeromonas, Francisella, Moraxella, Pseudomonas,Campylobacter, and Helicobacter. Specific examples of Proteobacteriainclude: Rickettsia conorii, Rickettsia prowazekii, Rickettsia typhi,Ehrlichia bovis, Agrobacterium tumefaciens, Brucella melitensis,Rhizobium rhizogenes, Neisseria meningitides, Bordetella parapertussis,Bordetella pertussis, Burkholderi mallei, Burkholderi pseudomallei,Neisseria gonorrhoeae, Escherichia coli, Salmonella enterica, Salmonellatyphimurium, Yersinia pestis, Klebsiella pneumoniae, Yersiniaenterocolitica, Proteus vulgaris, Shigella flexneri, Shigella sonnei,Shigella dysenterica, Haemophilus influenzae, Pasteurella multocida,Actinobacillus actinomycetemcomitans, Actinobacillus pleuropneumoniae,Haemophilus somnus, Legionella pneumophila, Mannheimia haemolytica,Vibrio cholerae, Vibrio parahaemolyticus, Coxiella burnetii, Aeromonashydrophila, Aeromonas salmonicida, Francisella tularesis, Moraxellacatarrhalis, Pseudomonas aeruginosa, Pseudomonas putida, Campylobacterjejuni, and Helicobacter pylori.

Non-limiting examples of Spirochaetes include bacteria of the familiesBrachyspiraceae, Leptospiraceae, and Spirochaetaceae. Specific examplesof Spirochaetes include Borrelia burgdorferi, and Treponema pallidum.

2. Different Types of Biological Matter

Methods and apparatuses of the invention can be applied to organisms.Stasis of the organism can be induced or stasis within cells, tissues,and/or organs of the organism can be induced. Biological matter in whichstasis can be induced that are contemplated for use with methods andapparatuses of the invention are limited only insofar as the comprisecells utilizing oxygen to produce energy.

Stasis can be induced in cells, tissues, or organs involving the heart,lung, kidney, liver, bone marrow, pancreas, skin, bone, vein, artery,cornea, blood, small intestine, large intestine, brain, spinal cord,smooth muscle, skeletal muscle, ovary, testis, uterus, and umbilicalcord.

Moreover, stasis can be induced in cells of the following type:platelet, myelocyte, erythrocyte, lymphocyte, adipocyte, fibroblast,epithelial cell, endothelial cell, smooth muscle cell, skeletal musclecell, endocrine cell, glial cell, neuron, secretory cell, barrierfunction cell, contractile cell, absorptive cell, mucosal cell, limbuscell (from cornea), stem cell (totipotent, pluripotent or multipotent),unfertilized or fertilized oocyte, or sperm.

Moreover, stasis can be induced in plants or parts of plants, includingfruit, flowers, leaves, stems, seeds, cuttings. Plants can beagricultural, medicinal, or decorative. Induction of stasis in plantsmay enhance the shelf life or pathogen resistance of the whole or partof the plant.

Methods and apparatuses of the invention can be used to induce stasis inin vivo biological matter. This can serve to protect and/or preserve thebiological matter or the organism itself or to prevent damage or injury(or further damage or injury) to them or the organism overall.

3. Assays

Stasis can be measured by a number of ways, including by quantifying theamount of oxygen consumed by a biological sample, the amount of carbondioxide produced by the sample (indirect measurement of cellularrespiration), or characterizing motility.

To determine the rate of consumption of oxygen or the rate of productionof carbon dioxide the biological matter is placed into a chamber that issealed with two openings; for gas import and export. Gas (room air orother gases) is passed into the chamber at a given flow rate and out ofthe exit port to maintain approximately 1 atmosphere of pressure in thechamber. Before and after exposure to the chamber the gas is passedthrough a carbon dioxide detector and or an oxygen detector to measure(every second) the amount of each compound in the gas mixture.Comparison of these values over time gives the rate of oxygenconsumption or carbon dioxide production.

II. Oxygen Antagonists and Other Active Compounds

The present invention concerns methods, compositions and articles ofmanufacture involving one or more agents that can act on biogical matterso as to produce a number of effects, including, but not limited to,inducing stasis, enhancing or increasing survivability, reversiblyinhibiting metabolism, reducing cellular or organismal metabolism andactivity, reducing the oxygen requirement, reducing or preventingdamage, preventing ischemic damage, preventing aging or senescence,and/or a achieve a variety of therapeutic applications discussed herein.It certain embodiments, the agents are qualified as “active compounds.”

In some embodiments, the agent is an oxygen antagonist, which may actdirectly or indirectly. Oxygen metabolism is a fundamental requirementfor life in aerobic metazoans. Aerobic respiration accounts for the vastmajority of energy production in most animals and also serves tomaintain the redox potential necessary to carry out important cellularreactions. In hypoxia, decreased oxygen availability results ininefficient transfer of electrons to molecular oxygen in the final stepof the electron transport chain. This inefficiency results in both adecrease in aerobic energy production and an increase in the productionof damaging free radicals, mainly due to the premature release ofelectrons at complex III and the formation of O₂ ⁻ by cytochrome oxidase(Semenza, 1999). Limited energy supplies and free radical damage caninterfere with essential cellular processes such as protein synthesisand maintenance of membrane polarities (Hochachka et al., 1996), andwill ultimately lead to cell death.

In other embodiments, the agent is a protective metabolic agent.Metabolism is generally understood as referring to chemical processes(in a cell or organism) that are required for life; they involve avariety of reactions to sustain energy production and synthesize(anabolism) and break down (catabolism) complex molecules.

In certain embodiments of the invention, an active compound has achemical structure as set forth as Formula I or IV described herein, oris a precursor of Formula I or IV.

A variety of chemical structures and compounds are described herein. Thefollowing definitions apply to terms used to described these structuresand compounds discussed herein:

“Alkyl,” where used, either alone or within other terms such as“arylalkyl”, “aminoalkyl”, “thioalkyl” “cyanoalkyl” and “hydroxyalkyl”,refers to linear or branched radicals having one to about twenty carbonatoms. The term “lower alkyl” refers to C₁-C₆ alkyl radicals. As usedherein the term alkyl includes those radicals that are substituted withgroups such as hydroxy, halo (such as F, Cl, Br, I), haloalkyl, alkoxy,haloalkoxy, alkylthio, cyano, isocyano, carboxy (—COOH), alkoxycarbonyl,(—COOR), acyl, acyloxy, amino, alykamino, urea (—NHCONHR), thiol,alkylthio, sulfoxy, sulfonyl, arylsulfonyl, alkylsulfonyl, sulfonamido,arylsulfonamido, heteroaryl, heterocyclyl, heterocycloalkyl, amidyl,alkylimino carbonyl, amidino, guanidono, hydrazino, hydrazide, sodiumsulfonyl (—SO₃Na), sodium sulfonylalkyl (—R SO₃Na). Examples of suchradicals include, but are not limited to, methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl,hexyl and the like.

“Hydroxyalkyl” refers to an alkyl radical, as defined herein,substituted with one or more hydroxyl radicals. Examples of hydroxyalkylradicals include, but are not limited to, hydroxymethyl, 2-hydroxyethyl,2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl, 3-hydroxybutyl,4-hydroxybutyl, 2,3-dihydroxypropyl, 1-(hydroxymethyl)-2-hydroxyethyl,2,3-dihydroxybutyl, 3,4-dihydroxybutyl, and2-(hydroxymethyl)-3-hydroxypropyl, and the like.

“Arylalkyl” refers to the radical R′R— wherein an alkyl radical, “R” issubstituted with an aryl radical “R′.” Examples of arylalkyl radicalsinclude, but are not limited to, benzyl, phenylethyl, 3-phenylpropyl,and the like.

“Aminoalkyl” refers to the radical H₂NR′—, wherein an alkyl radical issubstituted with am amino radical. Examples of such radicals includeaminomethyl, amino ethyl, and the like. “Alkylaminoalkyl” refers to analkyl radical substituted with an alkylamino radical.

“Alkylsulfonamido” refers to a sulfonamido group (—S(O)₂—NRR′) appendedto an alkyl group, as defined herein.

“Thioalkyl” refers to wherein an alkyl radical is substituted with oneor more thiol radicals. “Alkylthioalkyl” refers to wherein an alkylradical is substituted with one or more alkylthio radicals. Examplesinclude, but are not limited to, methylthiomethyl, ethylthioisopropyl,and the like. Arylthioalkyl” refers to wherein an alkyl radical, asherein defined, is substituted with one or more arylthio radicals.

“Carboxyalkyl” refers to the radicals —RCO₂H, wherein an alkyl radicalis substituted with a carboxyl radical. Example include, but are notlimited to, carboxymethyl, carboxyethyl, carboxypropyl, and the like.

“Alkylene” refers to bridging alkyl radicals.

The term “alkenyl” refers to an unsaturated, acyclic hydrocarbon radicalin so much as it contains at least one double bond. Such alkenylradicals contain from about 2 to about 20 carbon atoms. The term “loweralkenyl” refers to C₁-C₆ alkenyl radicals. As used herein, the termalkenyl radicals includes those radicals substituted as for alkylradicals. Examples of suitable alkenyl radicals include propenyl,2-chloropropenyl, buten-1-yl, isobutenyl, pent-1-en-1-yl,2-2-methyl-1-buten-1-yl, 3-methyl-1-buten-1-yl, hex-2-en-1-yl,3-hydroxyhex-1-en-1-yl, hept-1-en-1-yl, and oct-1-en-1-yl, and the like.

The term “alkynyl” refers to an unsaturated, acyclic hydrocarbon radicalin so much as it contains one or more triple bonds, such radicalscontaining about 2 to about 20 carbon atoms. The term “lower alkynyl”refers to C₁-C₆ alkynyl radicals. As used herein, the term alkynylradicals includes those radicals substituted as for alkyl radicals.Examples of suitable alkynyl radicals include ethynyl, propynyl,hydroxypropynyl, but-1-yn-1-yl, but-1-yn-2-yl, pent-1-yn-1-yl,pent-1-yn-2-yl, 4-methoxypent-1-yn-2-yl, 3-methylbut-1-yn-1-yl,hex-1-yn-1-yl, hex-1-yn-2-yl, hex-1-yn-3-yl, 3,3-dimethyl-1-butyn-1-ylradicals and the like

“Alkoxy,” refers to the radical R′O—, wherein R′ is an alkyl radical asdefined herein. Examples include, but are not limited to, methoxy,ethoxy, propoxy, butoxy, isopropoxy, tert-butoxy alkyls, and the like.Alkoxyalkyl” refers to alkyl radicals substituted by one or more alkoxyradicals. Examples include, but are not limited to, methoxymethyl,ethoxyethyl, methoxyethyl, isopropoxyethyl, and the like.

“Alkoxycarbonyl” refers to the radical R—O—C(O)—, wherein R is an alkylradical as defined herein. Examples of alkoxycarbonyl radicals include,but are not limited to, methoxycarbonyl, ethoxycarbonyl,sec-butoxycarbonyl, isoprpoxycarbonyl, and the like. Alkoxythiocarbonylrefers to R—O—C(S)—.

“Aryl” refers to the monovalent aromatic carbocyclic radical consistingof one individual ring, or one or more fused rings in which at least onering is aromatic in nature, which can optionally be substituted with oneor more, preferably one or two, substituents such as hydroxy, halo (suchas F, Cl, Br, I), haloalkyl, alkoxy, haloalkoxy, alkylthio, cyano,carboxy (—COOH), alkoxycarbonyl, (—COOR), acyl, acyloxy, amino,alykamino, urea (—NHCONHR), thiol, alkylthio, sulfoxy, sulfonyl,arylsulfonyl, alkylsulfonyl, sulfonamido, arylsulfonamido, heteroaryl,heterocyclyl, heterocycloalkyl, amidyl, alkylimino carbonyl, amidino,guanidono, hydrazino, hydrazide, sodium sulfonyl (—SO₃Na), sodiumsulfonylalkyl (—R SO₃Na), unless otherwise indicated. Alternatively twoadjacent atoms of the aryl ring may be substituted with a methylenedioxyor ethylenedioxy group. Examples of aryl radicals include, but are notlimited to, phenyl, naphthyl, biphenyl, indanyl, anthraquinolyl,tert-butyl-phenyl, 1,3-benzodioxolyl, and the like.

“Arylsulfonamido” refers to a sulfonamido group, as defined herein,appended to an aryl group, as defined herein.

“Thioaryl” refers to an aryl group substituted with one or more thiolradicals.

“Alkylamino” refers to amino groups that are substituted with one or twoalkyl radicals. Examples include monosubstituted N-alkylamino radicalsand N,N-dialkylamino radicals. Examples include N-methylamino,N-ethylamino, N,N-dimeythylamino N,N-diethylamino, N-methyl,N-ethyl-amino, and the like.

“Aminocarbonyl” refers to the radical H₂NCO—. “Aminocarbonyalkyl” refersto the substitution of an alkyl radical, as herein defined, by one ormore aminocarbonyl radicals.

“Amidyl” refers to RCO—NH—, wherein R is a H or alkyl, aryl, orheteroaryl, as defined herein.

“Imino carbonyl” refers to a carbon radical having two of the fourcovalent bond sites shared with an imino group. Examples of such iminocarbonyl radicals include, for example, C═NH, C═NCH₃, C═NOH, andC═NOCH₃. The term “alkylimino carbonyl” refers to an imino radicalsubstituted with an alkyl group, The term “amidino” refers to asubstituted or unsubstituted amino group bonded to one of two availablebonds of an iminocarbonyl radical. Examples of such amidino radicalsinclude, for example, NH₂—C═NH, NH₂—C═NCH₃, NH—C═NOCH₃ andNH(CH₃)—C═NOH. The term “guanidino” refers to an amidino group bonded toan amino group as defined above where said amino group can be bonded toa third group. Examples of such guanidino radicals include, for example,NH₂—C(NH)—NH—, NH₂—C(NCH₃)—NH—, NH₂—C(NOCH₃)—NH—, and CH₃NH—C(NOH)—NH—.The term “hydrazino” refers to —NH—NRR′, where R and R′ areindependently hydrogen, alkyl and the like. “Hydrazide” refers to—C(═O)—NH—NRR′.

The term “heterocyclyl” refers to saturated and partially saturatedheteroatom-containing ring-shaped radicals having from 4 through 15 ringmembers, herein referred to as “C₄-C₁₅ heterocyclyl” selected fromcarbon, nitrogen, sulfur and oxygen, wherein at least one ring atom is aheteroatom. Heterocyclyl radicals may contain one, two or three ringswherein such rings may be attached in a pendant manner or may be fused.Examples of saturated heterocyclic radicals include saturated 3 to6-membered heteromonocylic group containing 1 to 4 nitrogen atoms [e.g.pyrrolidinyl, imidazolidinyl, piperidino, piperazinyl, etc]; saturated 3to 6-membered heteromonocyclic group containing 1 to 2 oxygen atoms and1 to 3 nitrogen atoms [e.g. morpholinyl, etc.]; saturated 3 to6-membered heteromonocyclic group containing 1 to 2 sulfur atoms and 1to 3 nitrogen atoms [e.g., thiazolidinyl, etc.]. Examples of partiallysaturated heterocyclyl radicals include dihydrothiophene, dihydropyran,dihydrofuran and dihydrothiazole. Non-limiting examples of heterocyclicradicals include 2-pyrrolinyl, 3-pyrrolinyl, pyrrolindinyl,1,3-dioxolanyl, 2H-pyranyl, 4H-pyranyl, piperidinyl, 1,4-dioxanyl,morpholinyl, 1,4-dithianyl, thiomorpholinyl, and the like. Suchheterocyclyl groups may be optionally substituted with groups such assubstituents such as hydroxy, halo (such as F, Cl, Br, I), haloalkyl,alkoxy, haloalkoxy, alkylthio, cyano, carboxy (—COOH), alkoxycarbonyl,(—COOR), acyl, acyloxy, amino, alykamino, urea (—NHCONHR), thiol,alkylthio, sulfoxy, sulfonyl, arylsulfonyl, alkylsulfonyl, sulfonamido,arylsulfonamido, heteroaryl, heterocyclyl, heterocycloalkyl, amidyl,alkylimino carbonyl, amidino, guanidono, hydrazino, hydrazide, sodiumsulfonyl (—SO₃Na), sodium sulfonylalkyl (—RSO₃Na).

“Hetroaryl” refers to monovalent aromatic cyclic radicals having one ormore rings, preferably one to three rings, of four to eight atoms perring, incorporating one or more heteroatoms, preferably one or two,within the ring (chosen from nitrogen, oxygen, or sulfur), which canoptionally be substituted with one or more, preferably one or twosubstituents selected from substituents such as hydroxy, halo (such asF, Cl, Br, I), haloalkyl, alkoxy, haloalkoxy, alkylthio, cyano, carboxy(—COOH), alkoxycarbonyl, (—COOR), acyl, acyloxy, amino, alykamino, urea(—NHCONHR), thiol, alkylthio, sulfoxy, sulfonyl, arylsulfonyl,alkylsulfonyl, sulfonamido, arylsulfonamido, heteroaryl, heterocyclyl,heterocycloalkyl, amidyl, alkylimino carbonyl, amidino, guanidono,hydrazino, hydrazide, sodium sulfonyl (—SO₃Na), sodium sulfonylalkyl(—RSO₃Na), unless otherwise indicated. Examples of heteroaryl radicalsinclude, but are not limited to, imidazolyl, oxazolyl, thiazolyl,pyrazinyl, thienyl, furanyl, pyridinyl, quinolinyl, isoquinolinyl,benzofuryl, benzothiophenyl, benzothiopyranyl, benzimidazolyl,benzoxazolyl, benzothiazolyl, benzopyranyl, indazolyl, indolyl,isoindolyl, quinolinyl, isoquinolinyl, naphthyridinyl,benezenesulfonyl-thiophenyl, and the like.

“Heteroaryloxy” refers to heteroaryl radicals attached to an oxyradical. Examples of such radicals include, but are not limited to,2-thiophenyloxy, 2-pyrimidyloxy, 2-pyridyloxy, 3-pyridyloxy,4-pyridyloxy, and the like

“Heteroaryloxyalkyl” refers to alkyl radicals substituted with one ormore heteroaryloxy radicals. Examples of such radicals include2-pyridyloxymethyl, 3-pyridyloxyethyl, 4-pyridyloxymethyl, and the like.

“Cycloalkyl” refers to monovalent saturated carbocyclic radicalsconsisting of one or more rings, typically one or two rings, of three toeight carbons per ring, which can typically be substituted with one ormore, substitutents hydroxy, halo (such as F, Cl, Br, I), haloalkyl,alkoxy, haloalkoxy, alkylthio, cyano, carboxy (—COOH), alkoxycarbonyl,(—COOR), acyl, acyloxy, amino, alykamino, urea (—NHCONHR), thiol,alkylthio, sulfoxy, sulfonyl, arylsulfonyl, alkylsulfonyl, sulfonamido,arylsulfonamido, heteroaryl, heterocyclyl, heterocycloalkyl, amidyl,alkylimino carbonyl, amidino, guanidono, hydrazino, hydrazide, sodiumsulfonyl (—SO₃Na), sodium sulfonylalkyl (—R SO₃Na), unless otherwiseindicated. Examples of cycloalkyl radicals include, but are not limitedto, cyclopropyl, cyclobutyl, 3-ethylcyclobutyl, cyclopentyl,cycloheptyl, and the like.

“Cycloalkenyl” refers to radicals having three to ten carbon atoms andone or more carbon-carbon double bonds. Typical cycloalkenyl radicalshave three to seven carbon atoms. Examples include cyclobutenyl,cyclopentenyl, cyclohexenyl, cycloheptenyl, and the like“Cycloalkenylalkyl” refers to radicals wherein an alkyl radical, asdefined herein, is substituted by one or more cycloalkenyl radicals.

“Cylcoalkoxy” refers to cycloalkyl radicals attached to an oxy radical.Examples include, but are not limited to, cyclohexoxy, cyclopentoxy andthe like.

“Cylcoalkoxyalkyl” refers to alkyl radicals substituted one or morecycloalkoxy radicals. Examples include cyclohexoxyethyl,cyclopentoxymethyl, and the like. Sulfinyl” refers to —S(O)—.

“Sulfonyl” refers to —S(O)₂—, wherein “alkylsulfonyl” refers to asulfonyl radical substituted with an alkyl radical, RSO₂—, arylsulfonylrefers to aryl radicals attached to a sulfonyl radical. “Sulfonamido”refers to —S(O)₂—NRR′.

“Sulfonic acid” refers to —S(O)₂OH. “Sulfonic ester” refers to —S(O)₂OR,wherein R is a group such as an alkyl as in sulfonic alkyl ester.

“Thio” refers to —S—. “Alkylthio” refers to RS— wherein a thiol radicalis substituted with an alkyl radical R. Examples include methylthio,ethylthio, butlythio, and the like. “Arylthio” refers to RS—, wherein athio radical is substituted with an aryl radical, as herein defined.“Examples include, but are not limited to, phenylthio, and the like.Examples include, but are not limited to, phenylthiomethyl and the like.

“Alkylthiosulfonic acid” refers to the radical HO₃SR′S—, wherein analkylthioradical is substituted with a sulfonic acid radical.

“Thiosulfenyl” refers to —S—SH.

“Acyl”, alone or in combination, refers to a carbonyl or thionocarbonylgroup bonded to a radical selected from, for example, hydrido, alkyl,alkenyl, alkynyl, haloalkyl, alkoxy, alkoxyalkyl, haloalkoxy, aryl,heterocyclyl, heteroaryl, alkylsulfinylalkyl, alkylsulfonylalkyl,aralkyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, alkylthio, arylthio,amino, alkylamino, dialkylamino, aralkoxy, arylthio, and alkylthioalkyl.Examples of “acyl” are formyl, acetyl, benzoyl, trifluoroacetyl,phthaloyl, malonyl, nicotinyl, and the like.

The term “acylthiol” and “acyldisulfide” refers to the radicals RCOS-and RCOSS-respectively.

The term “thiocarbonyl” refers to the compounds and moieties whichcontain a carbon connected with a double bond to a sulfur atom —C(═S)—.“Alkylthiocarbonyl” refers to wherein a thiocarbonyl group issubstituted with an alkyl radical, R. as defined herein, to form themonovalent radical RC(═S)—. “Aminothiocarbonyl” refers to a thiocarbonylgroup substituted with an amino group, NH₂C(═S)—.

“Carbonyloxy” refers to —OCOR.

“Alkoxycarbonyl” refers to —COOR.

“Carboxyl” refers to —COOH.

For those compounds with stereoisomers, all stereoisomers thereof,including cis/trans geometric isomers, diastereomers and the individualenantiomers are contemplated

A. Carbon Monoxide

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas thatcan be toxic to animals, including humans. According to the Center forDisease Control, more than 450 people unintentionally die from carbonmonoxide each year.

It can be toxic to organisms whose blood carries oxygen to sustain itssurvival. It may be poisonous by entering the lungs through normalbreathing and displacing oxygen from the bloodstream. Interruption ofthe normal supply of oxygen jeopardizes the functions of the heart,brain and other vital functions of the body. However, the use of carbonmonoxide for medical applications is being explored (Ryter et al.,2004).

At amounts of 50 parts per million (ppm), carbon monoxide presents nosymptoms to humans exposed to it. However, at 200 ppm, within two-threehours the carbon monoxide can cause a slight headache; at 400 ppm,within one to two hours it can cause a frontal headache that may becomewidespread within three hours; and, at 800 ppm it can cause dizziness,nausea, and/or convulsions within 45 minutes, and render the subjectinsensible within two hours. At levels of around 1000 ppm, an organismcan expire after exposure for more than around 1-2 minutes.

Because of the well-known and well-documented toxic effects of carbonmonoxide to an organism, it is thus surprising and unexpected thatcarbon monoxide can be used to induce stasis of and/or help preservelive biological samples. It is thus contemplated that carbon monoxidecan be used for inducing stasis in isolated biological matter, such asblood-free biological matter (because of the effects that carbonmonoxide has with respect to hemoglobin, which is a separate pathwaythan the one involved in inducing stasis).

In addition to exposure to carbon monoxide either to induce stasis or tolimit or prevent any damage caused by a stasis-inducing agent, theinvention contemplates that carbon monoxide may be used in combinationwith agents or methods that assist in the preservation and/ortransplantation/grafting process of biological materials.

B. Chalcogenide Compounds

Compounds containing a chalcogen element; those in Group 6 of theperiodic table, but excluding oxides, are commonly termed“chalcogenides” or “chalcogenide compounds (used interchangeablyherein). These elements are sulfur (S), selenium (Se), tellurium (Te)and polonium (Po). Common chalcogenides contain one or more of S, Se andTe, in addition to other elements. Chalcogenides include elemental formssuch as micronized and/or nanomilled particles of S and Se. Chalcogenidecompounds can be employed as reducing agents.

The present inventor, though not bound by the following theory, believesthat the ability of chalcogenides to induce stasis in cells, and topermit modulation of core body temperature in animals, stems from thebinding of these molecules to cytochrome oxidase. In so doing,chalcogenides inhibit or reduce the activity of oxidativephosphorylation. The ability of chalcogenides to block autonomousthermoregulation, i.e., to permit core body temperatures of“warm-blooded” animals to be manipulated through control ofenvironmental temperatures, is believed to stem from the same mechanismas set forth above—binding to cytochrome oxidase, and blocking orreducing the activity of oxidative phosphorylation. Chalcogenides may beprovided in liquid as well as gaseous forms.

Chalcogenides can be toxic, and at some levels lethal, to mammals. Inaccordance with the present invention, it is anticipated that the levelsof chalcogenide should not exceed lethal levels in the appropriateenvironment. Lethal levels of chalcogenides may be found, for example inMaterial Safety Data Sheets for each chalcogenide or from informationsheets available from the Occupational Safety and Health Administration(OSHA) of the US Government.

While carbon monoxide and chalcogenide compounds can both induce stasisby acting as an oxygen antagonist, they have different toxic effectsthat are separate from their abilities to induce stasis. Moreover, theconcentrations needed to mediate a stasis effect are different becauseof the different affinities of cytochrome oxidase. While the affinity ofcytochrome oxidase for oxygen is about 1:1 as compared to carbonmonoxide, the affinity for H₂S appears on the order of about 300:1 ascompared to oxygen. This impacts what toxic effects are observed with astasis-inducing concentration. Thus, it is contemplated thatchalcogenide compounds are particularly suited for inducing stasis ofbiological matter in whole organisms and of whole organisms.

It also may prove useful to provide additional stimuli to a biologicalmatter before withdrawing the chalcogenide. In particular, it isenvisioned that one may subject an animal to increased ambienttemperature prior to removing the source of chalcogenide.

1. H₂S and Other Sulfur Containing Compounds

Hydrogen sulfide (H₂S) is a potentially toxic gas that is oftenassociated with petrochemical and natural gas, sewage, paper pulp,leather tanning, and food processing. The primary effect, at thecellular level, appears to be inhibition of cytochrome oxidase and otheroxidative enzymes, resulting in cellular hypoxia. Exposure to extremelevels (500 ppm) results in sudden collapse and unconsciousness, aso-called “knockdown” effect, followed by recovery. Post-exposureeffects may persist for years, and include loss of coordination, memoryloss, motor dysfunction, personality changes, hallucination andinsomnia.

Most contact with H₂S, however, occurs well below such acute toxicitylevels. Nonetheless, there is general concern over long term contact atsub-acute levels. Some reports exist indicating persistent impairmentsin balance and memory, as well as altered sensory motor functions mayoccur in humans following chronic low-level H₂S exposure. Kilburn andWarshaw (1995); Kilburn (1999). Others have reported that perinatalexposure of rats to low (20 or 50 ppm) H₂S for 7 hours per day fromgestation through post-natal day 21 resulted in longer dendriticbranches with reduced aborization of cerebellar Purkinje cells. Otherneurologic defects associated with relatively low levels of H₂S includealtered brain neurotransmitter concentrations and altered neurologicresponses, such as increased hippocampal theta EEG activity.

Behavioral toxicity was studied in rats exposed to moderate levels ofH₂S. The results showed that H₂S inhibits discriminated avoidanceresponses immediately after the end of the exposure (Higuchi andFukamachi, 1997), and also interferes with the ability of rats to learna baited radial arm maze task (Partlo et al., 2001). In anotherperinatal study using 80 ppm H₂S, no neuropathological effects oraltered motor activity, passive avoidance, or acoustic startle responsein exposed rat pups was seen. Dorman et al. (2000). Finally, Struve etal. (2001) exposed rats to H₂S by gas at various levels for 3 hours perday on five consecutive days. Significant reductions in motor activity,water maze performance and body temperature following exposure to 80 ppmor greater H₂S were observed. Taken together, these reports indicatethat H₂S can have a variety of effects on the biochemistry of mammaliantissues, but there is no clear pattern of response in terms of behavior.

Once dissolved in plasma, H₂S will be involved in a series of chemicalreactions. The chemical reactions are: (1) the dissociation of themolecular H₂S to form the bisulfide ion, (2) the dissociation of thebisulfide ion to the sulfide ion, and (3) the self ionization of water.The reactions are given below:

H₂S_((aq))

HS_((aq)) ⁻+H_((aq)) ⁺

HS_((aq)) ⁻

S_((aq)) ⁻²+H_((aq)) ⁺

H₂O

H_((aq)) ⁺+OH_((aq)) ⁻

Using the equilibrium constants K₁=1.039 E-07, K₂=6.43 E⁻¹⁶ andK_(w)=1.019 E⁻¹⁴, at pH 7.4 the calculated amount of the differentspecies relative to the total S concentration are approximately 23% H₂Sand 77% HS⁻, while the amount of S²⁻ tends to zero.

The inventor uses an extractive alkylation technique coupled with gaschromatography and mass specific detection to quantify hydrogen sulfide(adapted from Hyspler et al., 2002). This method involves firstly addinga 50 μL sample of blood, serum or tissue extract that has been dilutedin nitrogen purged deoxygenated water to a concentration of 1 mg/mL,together with 150 μL of a reaction buffer consisting of 5 mMbenzalkonium chloride (BZK) in a saturated borate buffer. Added to thisis first, 100 μL of a 15 μM solution of 4-chloro-benzyl methyl sulfide(4CBMS) in ethyl acetate and then 100 μL of a 20 mM solution ofpentafluorobenzylbromide (PFBBr) in toluene. This solution is thensealed and incubated at 55° C. with rotation or shaking for 2 hr. Afterthis incubation period, 200 μL of a saturated solution of KH₂PO₄ is thenadded, and the organic phase is removed and analyzed by gaschromatography and mass specific detection according to the methodsdescribed in Hyspler et al., 2002. These measurements are then comparedto a standard curve generated using the same method described above,beginning with known standard concentrations ranging from 1 μM to 1 mMof Na₂S prepared in nitrogen purged deoxygenated H₂O, in order todetermine the concentration of endogenous hydrogen sulfide levels. Inorder to analyze bound and/or oxidized sulfide levels, the same methodis applied, except that a denaturing/reducing reaction buffer is used,which consists of 5 mM BZK with 1% tetraethylammonium hydroxide (TEAH)and 1 mM tris(2-carboxyethyl)-phosphine hydrochloride (TCEP) insaturated borate buffer, instead of the reaction buffer described above.

Typical levels of hydrogen sulfide contemplated for use in accordancewith the present invention include values of about 1 to about 150 ppm,about 10 to about 140 ppm, about 20 to about 130 ppm, and about 40 toabout 120 ppm, or the equivalent oral, intravenous or transdermal dosagethereof. Other relevant ranges include about 10 to about 80 ppm, about20 to about 80 ppm, about 10 to about 70 ppm, about 20 to about 70 ppm,about 20 to about 60 ppm, and about 30 to about 60 ppm, or theequivalent oral, intravenous or transdermal thereof. It also iscontemplated that, for a given animal in a given time period, thechalcogenide atmosphere should be reduced to avoid a potentially lethalbuild up of chalcogenide in the subject. For example, an initialenvironmental concentration of 80 ppm may be reduced after 30 min to 60ppm, followed by further reductions at 1 hr (40 ppm) and 2 hrs (20 ppm).

a. H₂S Precursors

The present invention also concerns the use of compounds and agents thatcan yield H₂S under certain conditions, such as upon exposure, or soonthereafter, to biological matter. It is contemplated that suchprecursors yield H₂S upon one or more enzymatic or chemical reactions.

3. Other Chalcogenides

In certain embodiments, the reducing agent structure compound isdimethylsulfoxide (DMSO), dimethylsulfide (DMS), methylmercaptan(CH₃SH), mercaptoethanol, thiocyanate, hydrogen cyanide, methanethiol(MeSH), or CS₂. In particular embodiments, the oxygen antagonist is CS₂,MeSH, or DMS. Compounds on the order of the size of these molecules areparticularly contemplated (that is, within about 50% of their molecularweights).

Additional compounds that are envisioned as useful for inducing stasisinclude, but are not limited to, the following structures, many of whichare readily available and known to those of skill in the art (identifiedby CAS number): 104376-79-6 (Ceftriaxone Sodium Salt); 105879-42-3;1094-08-2 (Ethopropatine HCl); 1098-60-8 (Triflupromazine HCl);111974-72-2; 113-59-7; 113-98-4 (Penicillin G K⁺); 115-55-9; 1179-69-7;118292-40-3; 119478-56-7; 120138-50-3; 121123-17-9; 121249-14-7;1229-35-2; 1240-15-9; 1257-78-9 (Prochlorperazine Edisylate Salt);128345-62-0; 130-61-0 (Thioridazine HCl) 132-98-9 (Penicillin V K⁺);13412-64-1 (Dicloxacillin Na⁺ Hydrate); 134678-17-4; 144604-00-2;146-54-3; 146-54-5 (Fluphenazine 2HCl); 151767-02-1; 159989-65-8;16960-16-0 (Adrenocorticotropic Hormone Fragment 1-24); 1982-37-2;21462-39-5 (Clindamycin HCl); 22189-31-7; 22202-75-1; 23288-49-5(Probucol); 23325-78-2; 24356-60-3 (Cephapirin); 24729-96-2(Clindamycin); 25507-04-4; 26605-69-6; 27164-46-1 (Cefazolin Na⁺);2746-81-8; 29560-58-8; 2975-34-0; 32672-69-8 (Mesoridazine BenzeneSulfonate); 32887-01-7; 33286-22-5 ((⁺)-cis-Diltiazem HCl); 33564-30-6(Cefoxitin Na⁺); 346-18-9; 3485-14-1; 3511-16-8; 37091-65-9 (AzlocillinNa⁺); 37661-08-8; 3819-00-9; 38821-53-3 (Cephradine); 41372-02-5;42540-40-9 (Cefamandole Nafate); 4330-99-8 (Trimeprazinehemi-(⁺)-tartrate Salt); 440-17-5 Trifluoperazine 2HCl; 4697-14-7(Ticarcillin 2Na⁺); 4800-94-6 (Carbenicillin 2Na⁺); 50-52-2; 50-53-3;5002-47-1; 51481-61-9 (Cimetidine); 52239-63-1 (6-propyl-2-thiouracil);53-60-1 (Promazine HCl); 5321-32-4; 54965-21-8 (Albendazole); 5591-45-7(Thiothixene); 56238-63-2 (Cefuroxime Na⁺); 56796-39-5 (cefmetazoleNa⁺); 5714-00-1; 58-33-3 (Promethazine HCl); 58-38-8; 58-39-9(Perphenazine); 58-71-9 Cephalothin Na⁺); 59703-84-3 (Piperacillin Na⁺);60-99-1 (Methotrimeprazine Maleate Salt); 60925-61-3; 61270-78-8;6130-64-9 (Penicillin G Procaine Salt Hydrate); 61318-91-0 SulconazoleNitrate Salt); 61336-70-7 Amoxicillin Trihydrate); 62893-20-3Cefoperazone Na⁺); 64485-93-4 (Cefotaxime Na⁺); 64544-07-6; 64872-77-1;64953-12-4 Moxalactam Na⁺); 66104-23-2 (Pergolide Mesylate Salt);66309-69-1; 66357-59-3 (Ranitidine HCl); 66592-87-8 (Cefodroxil);68401-82-1; 69-09-0 (Chlorpromazine HCl); 69-52-3 (Ampicillin Na⁺);69-53-4 (Ampicillin); 69-57-8 Penicillin G Na⁺); 70059-30-2; 70356-03-5;7081-40-5; 7081-44-9 (Cloxacillin Na⁺H₂O); 7177-50-6 Nafcillin Na⁺H₂O);7179-49-9; 7240-38-2 (Oxacillin Na H₂O); 7246-14-2; 74356-00-6;74431-23-5; 74849-93-7; 75738-58-8; 76824-35-6 (Famotidine); 76963-41-2;79350-37-1; 81129-83-1; 84-02-6 (Prochlorperazine Dimaleate Salt);87-08-1 (Phenoxymethylpenicillinic Acid); 87239-81-4; 91-33-8(Benzthiazide); 91832-40-5; 94841-17-5; 99294-94-7; 154-42-7(6-Thioguanine); 36735-22-5; 536-33-4 (Ethionamide); 52-67-5(D-Penicillamine); 304-55-2 (Meso-2,3-Dimercaptosuccinic Acid); 59-52-92,3-Dimercapto⁺propanol 6112-76-1 (6-mercaptopurine); 616-91-1(N-acetyl-L-cysteine); 62571-86-2 (Captopril); 52-01-7 (spironolactone);and, 80474-14-2 (fluticasone propionate). Further compounds that arecontemplated as possibly useful for stasis include those with thechemical structure of Formulas I or IV.

C. Other Antagonists or Active Compounds and Related EnvironmentalConditions

1. Hypoxia and Anoxia

Hypoxia is a common natural stress and several well conserved responsesexist that facilitate cellular adaptation to hypoxic environments. Tocompensate for the decrease in the capacity for aerobic energyproduction in hypoxia, the cell must either increase anaerobic energyproduction or decrease energy demand (Hochachka et al., 1996). Examplesof both of these responses are common in metazoans and the particularresponse used depends, in general, on the amount of oxygen available tothe cell.

In mild hypoxia, oxidative phosphorylation is still partially active, sosome aerobic energy production is possible. The cellular response tothis situation, which is mediated in part by the hypoxia-inducibletranscription factor, HIF-1, is to supplement the reduced aerobic energyproduction by upregulating genes involved in anaerobic energyproduction, such as glycolytic enzymes and glucose transporters(Semenza, 2001; Guillemin et al., 1997). This response also promotes theupregulation of antioxidants such as catylase and superoxide dismutase,which guard against free radical-induced damage. As a result, the cellis able to maintain near normoxic levels of activity in mild hypoxia.

In an extreme form of hypoxia, referred to as “anoxia”-defined here as<0.001 kPa O₂—oxidative phosphorylation ceases and thus the capacity togenerate energy is drastically reduced. In order to survive in thisenvironment, the cell must decrease energy demand by reducing cellularactivity (Hochachka et al., 2001). For example, in turtle hepatocytesdeprived of oxygen, a directed effort by the cell to limit activitiessuch as protein synthesis, ion channel activity, and anabolic pathwaysresults in a 94% reduction in demand for ATP (Hochachka et al., 1996).In zebrafish (Danio rerio) embryos, exposure to anoxia leads to acomplete arrest of the heartbeat, movement, cell cycle progression, anddevelopmental progression (Padilla et al., 2001). Similarly, C. elegansrespond to anoxia by entering into suspended animation, in which allobservable movement, including cell division and developmentalprogression, ceases (Padilla et al., 2002; Van Voorhies et al., 2000).C. elegans can remain suspended for 24 hours or more and, upon return tonormoxia, will recover with high viability. This response allows C.elegans to survive the hypoxic stress by reducing the rate ofenergetically expensive processes and preventing the occurrence ofdamaging, irrevocable events such as aneuploidy (Padilla et al., 2002;Nystul et al., 2003).

One recently discovered response is the hypoxia-induced generation ofcarbon monoxide by heme oxygenase-1 (Dulak et al., 2003). Endogenouslyproduced carbon monoxide can activate signaling cascades that mitigatehypoxic damage through anti-apoptotic (Brouard et al., 2003) andanti-inflammatory (Otterbein et al., 2000) activity, and similarcytoprotective effects can be achieved in transplant models by perfusionwith exogenous carbon monoxide (Otterbein et al, 2003; Amersi et al.,2002). At higher concentrations, carbon monoxide competes with oxygenfor binding to iron-containing proteins, such as mitochondrialcytochromes and hemoglobin (Gorman et al., 2003), though thecytoprotective effect that this activity may have in hypoxia has notbeen investigated.

Despite the existence of these sophisticated defense mechanisms againsthypoxic damage, hypoxia is still often a damaging stress. For example,mammals have both heme oxygenase-1 and HIF-1, and some evidence suggeststhat suspended animation is possible in mammals as well (Bellamy et al.,1996; Alam et al., 2002). Yet, hypoxic damage due to trauma such asheart attack, stroke or blood loss is a major cause of death. Theunderstanding of the limitations of the two fundamental strategies forsurviving hypoxic stress, remaining animated or suspending animation, ishampered by the fact that it has been based on studies in a variety ofsystems under a variety of conditions.

“Hypoxia” occurs when the normal physiologic levels of oxygen are notsupplied to a cell or tissue. “Normoxia” refers to normal physiologiclevels of oxygen for the particular cell type, cell state or tissue inquestion. “Anoxia” is the absence of oxygen. “Hypoxic conditions” arethose leading to cellular hypoxia. These conditions depend on cell type,and on the specific architecture or position of a cell within a tissueor organ, as well as the metabolic status of the cell. For purposes ofthe present invention, hypoxic conditions include conditions in whichoxygen concentration is at or less than normal atmospheric conditions,that is less that 20.8, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9,8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0%; alternatively, these numbers couldrepresent the percent of atmosphere at 1 atmosphere of pressure (101.3kPa). An oxygen concentration of zero percent defines anoxic conditions.Thus, hypoxic conditions include anoxic conditions, although in someembodiments, hypoxic conditions of not less than 0.5% are implemented.As used herein, “normoxic conditions” constitute oxygen concentrationsof around 20.8% or higher.

Standard methods of achieving hypoxia or anoxia are well established andinclude using environmental chambers that rely on chemical catalysts toremove oxygen from the chamber. Such chambers are available commerciallyfrom, for example, BD Diagnostic Systems (Sparks, Md.) as GASPAKDisposable Hydrogen+Carbon Dioxide Envelopes or BIO-BAG EnvironmentalChambers. Alternatively, oxygen may be depleted by exchanging the air ina chamber with a non-oxygen gas, such as nitrogen. Oxygen concentrationmay be determined, for example using a FYRITE Oxygen Analyzer(Bacharach, Pittsburgh Pa.).

It is contemplated that methods of the invention can use a combinationof exposure to oxygen antagonist or other active compound and alterationof oxygen concentrations compared to room air. Moreover, the oxygenconcentration of the environment containing biological matter can beabout, at least about, or at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82,83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or100%, or any range derivable therein. Moreover, it is contemplated thata change in concentration can be any of the above percentages or ranges,in terms of a decrease or increase compared to room air or to acontrolled environment.

D. Mitochondrial Targeting Agents

Selectively targeting mitochondria is considered an embodiment of theinvention in some aspects so as to enhance activity. Such selectivemitochondrial targeting has been accomplished by conjugating agents to alipophilic triphenylphosphonium cation, which readily cross lipidbilayers and accumulate approximately a 1000 fold within themitochondrial matrix drive by the large potential (150 to −180 mv)across the mitochondrial inner membrane. Analogs of both vitamin E andubiquinone have been prepared and used to successfully targetmitochondria. (Smith et al., 1999; Kelso et al., 2001; Dhanasekaran etal., 2004). A thiol, thibutyltriphosphonium bromide (shown below), hasbeen prepared and used to target mitochondria wherein it accumulatedseveral hundred-fold (Burns et al., 1995; Burns & Murphey), 1997).

Such conjugates would appear to be suitable candidates for activecompounds. In addition to free thiol agents, thiosulfenyl substitutedcompounds, (H—S—S—R) may be useful. It is contemplated that in someembodiments the agents have the structure:

-   -   where Z is P or N;    -   R¹, R² and R³ are aryl, hetroaryl, alkylaryl, cycloalkyl, or        alkyl (suitably phenyl, benzyl, tolyl, pyridyl, cyclohexyl,        C₃-C₁₀ alkyl, optionally halogenated);    -   R⁴ is —R⁵SR⁶, wherein R⁵ is C₁-C₁₀ alkyl R⁶ is H or SO₃H, or        PO₃H.

III. Testing for Stasis

Various compounds useful for inducing stasis may be initially evaluatedusing a variety of different tests. Stasis can be measured by a numberof ways, including by quantifying the amount of oxygen consumed by abiological sample, the amount of carbon dioxide produced by the sample(indirect measurement of cellular respiration), or characterizingmotility.

To determine the rate of consumption of oxygen or the rate of productionof carbon dioxide the biological matter is placed into a chamber that issealed with two openings; for gas import and export. Gas (room air orother gases) is passed into the chamber at a given flow rate and out ofthe exit port to maintain approximately 1 atmosphere of pressure in thechamber. Before and after exposure to the chamber the gas is passedthrough a carbon dioxide detector and or an oxygen detector to measure(every second) the amount of each compound in the gas mixture.Comparison of these values over time gives the rate of oxygenconsumption or carbon dioxide production.

Other screens to identify candidate active stasis compounds have beenestablished. These screens and variations of thereof may be employed aspart of the invention or to implement aspects of the invention.

A. Assays with Zebrafish

A screening assay for stasis inducers was established using 48 hour oldzebrafish (D. rerio) embryos. These embryos are transparent, allowingone to view, using a dissecting microscope with a 4-20 times powerlense, the heart beat and resultant blood flow into the main vesselalong the back and into the tail. Heart rate in these animals is anindicator of the metabolic activity of the organism, such that areduction in the heart rate signifies a reduction in metabolism. Embryoswere dissected from their egg casings and distributed five per well inflat bottomed polystyrene tissue culture plates and incubated in 1 mL ofstandard fish water. The Dishwater is composed of 1 teaspoon InstantOcean (artificial sea water mixture, Aquarium Systems, Inc.) per 5gallons. Calcium chloride is adjusted to 150 ppm and sodium bicarbonateto 100 ppm. Conductivity of the water is at 900 microsiemens and the pHis about 6.5-7.4. A solution of hydrogen sulfide was prepared bybubbling a mixture of hydrogen sulfide (100 ppm) balanced with room airinto a flask containing 150 mL of fishwater at a rate of 100 cubiccentimeters per minute for 60-90 minutes. It was estimated that this wassufficient to achieve a saturated or nearly saturated or mostlysaturated solution of hydrogen sulfide. Based on the known solubility ofhydrogen sulfide in Ringer's solution at pH 7 at 1 atmosphere and roomtemperature, it was estimated that the fish water containedapproximately 0.1 molar hydrogen sulfide. Fish were exposed to thehydrogen sulfide solution and their heart rates were monitored over theensuing 24 hours by counting the number of beats per minute. Controlfish (exposed to fishwater alone) had heart beats of approximately160-200 beats per minute that did not change significantly over the 24hour observation period. By 2-3 hours following exposure to the hydrogensulfide-containing fishwater, heart beats were reduced by about half to60-80 beats per minute. By four hours, heart beats were reduced further,including some examples where the heart beat was zero or only a fewbeats per minute. After five hours of exposure, the hydrogen sulfidesolution was replaced with normal fishwater and the embryos were allowedto recover overnight at 28 degrees Celsius. By 24 hours after initialexposure to hydrogen sulfide, treated and rinsed animals displayed anormal heart rate of 160-200 beats per minute. Because hydrogen sulfidecaused the quiescence of the heart beat, in some cases to a standstill,followed by a return to normalcy, hydrogen sulfide was deemed to havebeen identified as a stasis inducer or other active compound by thecriteria of this screening assay.

B. Assays with Nematodes

A screening assay was established using nematodes (C. elegans).Nematodes do not survive well at 4 degrees Celsius, such that at 24hours at that temperature, they are all dead. Worms were exposed for Xminutes at room temperature to an atmosphere containing Y % carbonmonoxide, prior to exposing them to 4 degrees C. for 16 hrs. Compared tocontrol worms pre-exposed to room air which were all dead, carbonmonoxide treated worms survived with high viability after exposure tocold. Since carbon monoxide is a known stasis inducer in nematodes andneonatal human foreskin keratinocytes, the nematode assay is capable ofidentifying stasis inducing compounds as such by their ability toincrease the survivability of worms exposed to lethal hypothermia whenthe worms are pre-equilibrated in the stasis inducer or other activecompound.

IV. Therapeutic or Preventative Applications

A. Trauma

In certain embodiments, the present invention may find use in thetreatment of patients who are undergoing, or who are susceptible totrauma. Trauma may be caused by external insults, such as burns, wounds,amputations, gunshot wounds, or surgical trauma, internal insults, suchas stroke or heart attack that result in the acute reduction incirculation, or reductions in circulation due to non-invasive stress,such as exposure to cold or radiation. On a cellular level, trauma oftenresults in exposure of cells, tissues and/or organs to hypoxia, therebyresulting in induction of programmed cell death, or “apoptosis.”Systemically, trauma leads to the induction of a series of biochemicalprocesses, such as clotting, inflammation, hypotension, and may giverise to shock, which if it persists may lead to organ dysfunction,irreversible cell damage and death. Biological processes are designed todefend the body against traumatic insult; however they may lead to asequence of events that proves harmful and, in some instances, fatal.

Therefore, the present invention contemplates the placement of tissues,organs, limbs and even whole organisms into stasis as a way ofprotecting them from the detrimental effects of trauma. In a specificscenario, where medical attention is not readily available, induction ofstasis in vivo or ex vivo, alternatively in conjunction with reductionin the temperature of the tissue, organ or organism, can “buy time” forthe subject, either by bringing medical attention to the subject, or bytransporting the subject to the medical attention. The present inventionalso contemplates methods for inducing tissue regeneration and woundhealing by prevention/delay of biological processes that may result indelayed wound healing and tissue regeneration. In this context, inscenarios in which there is a substantial wound to the limb or organism,the induction of stasis induction of stasis in vivo or ex vivo,alternatively in conjunction with reduction in the temperature of thetissue, organ or organism, can aid in the wound healing and tissueregeneration process by managing the biological processes that inhibithealing and regeneration.

In addition to wound healing and hemorrhagic shock discussed below,methods of the invention can be implemented to prevent or treat traumasuch as cardiac arrest or stroke. The invention has particularimportance with respect to the risk of trauma from emergency surgicalprocedures, such as thoractomy, laparotomy, and splenic transection.

1. Wound Healing

In many instances, wounds and tissue damage are intractable or takeexcessive periods of time to heal. Examples are chronic open wounds(diabetic foot ulcers and stage 3 & 4 pressure ulcers), acute andtraumatic wounds, flaps and grafts, and subacute wounds (i.e., dehiscedincisions). This may also apply to other tissue damage, for exampleburns and lung damage from smoke/hot air inhalation.

Previous experiments show hibernation to be protective against injury(e.g., pin's in brains), therefore it may have healing effects.Consequently, this technology may be useful in the control of woundhealing processes, by bringing the tissue into a more metabolicallycontrolled environment. More particularly, the length of time that cellsor tissue are kept in stasis can vary depending on the injury. In someembodiments of the invention, biological matter is exposed to an oxygenantagonist or other active compound for about, at least about, or atmost about 30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45,50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2, 3, 4, 5, 6, 7 days, 1, 2, 3,4, 5 weeks, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 months or more.

2. Hematologic Shock (Hemorrhagic Shock) Shock is a life-threateningcondition that progresses rapidly when interventions are delayed. Shockis a state in which adequate perfusion to sustain the physiologic needsof organ tissues is not present. This is a condition of profoundhaemodynamic and metabolic disturbance characterized by failure of thecirculatory system to maintain adequate perfusion of vital organs. Itmay result from inadequate blood volume (hypovolaemic shock), inadequatecardiac function (cardiogenic shock) or inadequate vasomotor tone, alsoreferred to as distributive shock (neurogenic shock, septic shock,anaphylactic shock). This often results in rapid mortality of thepatient. Many conditions, including sepsis, blood loss, impairedautoregulation, and loss of autonomic tone, may produce shock orshocklike states. The present invention is anticipated to preventdetrimental effects of all the above states of shock, and sustain thelife of the biological matter undergoing such shock.

In hemorrhagic shock, blood loss exceeds the body's ability tocompensate and provide adequate tissue perfusion and oxygenation. Thisis frequently due to trauma, but may also be caused by spontaneoushemorrhage (e.g., gastrointestinal bleeding, childbirth), surgery, andother causes. Most frequently, clinical hemorrhagic shock is caused byan acute bleeding episode with a discrete precipitating event. Lesscommonly, hemorrhagic shock may be seen in chronic conditions withsubacute blood loss.

Physiologic compensation mechanisms for hemorrhage include initialperipheral and mesenteric vasoconstriction to shunt blood to the centralcirculation. This is then augmented by a progressive tachycardia.Invasive monitoring may reveal an increased cardiac index, increasedoxygen delivery (i.e., DO₂), and increased oxygen consumption (i.e.,VO₂) by tissues. Lactate levels, the acid-base status, and other markersalso may provide useful indicators of physiologic status. Age,medications, and comorbid factors all may affect a patient's response tohemorrhagic shock.

Failure of compensatory mechanisms in hemorrhagic shock can lead todeath. Without intervention, a classic trimodal distribution of deathsis seen in severe hemorrhagic shock. An initial peak of mortality occurswithin minutes of hemorrhage due to immediate exsanguination. Anotherpeak occurs after 1 to several hours due to progressive decompensation.A third peak occurs days to weeks later due to sepsis and organ failure.

In the United States, accidental injury is the leading cause ofmorbidity and mortality in persons between the ages of 1 and 44 years.In 2001, 157,078 resident deaths occurred as the result of injuries. Ofthese, 64.6 percent were classified as unintentional, 19.5 percent weresuicides, 12.9 percent were homicides, 2.7 percent were of undeterminedintent, and 0.3 percent involved legal intervention or operations ofwar. The leading causes of injury death were motor vehicle traffic,firearm, and falls. A large proportion of these fatalities result frommassive blood loss due to the trauma, leading to hemorrhagic shock.

In the majority of trauma injury cases, patients who come to ahospital's emergency department are treated by emergency physicians anddischarged without requiring surgery or care by a trauma service.However, patients with serious injuries require stabilization within the“Golden Hour” after the injury occurred, to improve the chances ofsurvival and to minimize disability.

As most shock cases are due to injury caused by an accident,pre-hospital care is critical to the survival of the patient. Thisinvolves rapid assessment, stabilization, and expeditious transport toan appropriate center for evaluation and definitive care. In allpatients with shock syndrome, the maintenance of a patent airway,adequate breathing and adequate circulation are the primary focus ofemergency treatment. Assessment is essential, as changes in clientcondition indicate progression of the shock syndrome. Early interventionis vital to minimize damage to tissues and organs and minimize permanentdisability and early identification of the primary clinical cause iscritical. Treatments are directed toward correcting the cause of theshock syndrome and slowing progression. Intravenous access and fluidresuscitation (typically IV saline) are standard, however, there is somedebate over this. Rapid reversal of hypovolemia may increase hemorrhage,dislodge partially formed clots, and dilute clotting factors.

Once at the emergency department, the focus is on optimizing perfusionand oxygenation of vital organs. Diagnosis and management of theunderlying hemorrhage must be performed rapidly and concurrently withmanagement of shock. There are two major stages of shock: earlycompensation stage and progressive stage. It is contemplated thatembodiments of the invention may be applied to patients in either orboth stages.

When hypovolemic shock results from massive hemorrage, the replacementfluid of choice is whole blood or packed red blood cells. Crystalloidsolutions will temporarily improve circulating volume, but the patientalso needs replacement of red blood cells to carry oxygen to thetissues. Management of shock focuses on fluid management, acid-basebalance, and improving myocardial contraction. Treating the underlyingcause of shock should also be treated in order to diminish theprogression of the shock syndrome. Whole body hibernation was induced inmice, and there was an immediate drop in overall metabolic state (asmeasured by CO₂ evolution). This was reversible, and the mice seem tofunction normally, even after repeated exposures. Accordingly, theinvention concerns inducing a whole body hibernetic state using H₂S (orother oxygen antagonist or other active compound), to preserve thepatient's vital organs and life. This will allow for transport to acontrolled environment (e.g., surgery), where the initial cause of theshock can be addressed, and then the patient brought back to normalfunction in a controlled manner. For this indication, the first hourafter injury, referred to as the “golden hour,” is crucial to asuccessful outcome. Stabilizing the patient in this time period is themajor goal, and transport to a critical care facility (e.g., emergencyroom, surgery, etc.) where the injury can be properly addressed. Thus,it would be ideal to maintain the patient in stasis to allow for thisand to address immediate concerns such as source of shock, replenishblood loss, and reestablish homeostasis. While this will varysignificantly, in most cases, the amount of time stasis will bemaintained is between about 6 and about 72 hours after injury. In someembodiments of the invention, biological matter is exposed to an oxygenantagonist or other active compound for about, at least about, or atmost about 30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45,50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2, 3, 4, 5, 6, 7 days or more,and any range or combination therein.

The biology of lethal hemorrhage and the physiological events that leadto shock and ultimately death are not fully understood. However, thereare mechanisms through which H₂S could reduce the lethal effects ofischemic hypoxia. Hydrogen sulfide inhibits cytochrome C oxidase andcould reduce oxygen demand by inhibiting this enzyme³. Decreased oxygendemand may reduce the deleterious effects of low oxygen levels includinga reduction of metabolic acidosis. Furthermore, tissue sulfydryl levelsdecrease during shock (Beck et al., 1954). Exogenous H₂S may preventthis hyposulfidic state and maintain sulfur homeostasis.

Hydrogen sulfide is naturally produced in animals and exhibits potentbiological activities (Kamoun, 2004). Most proteins contain disulfidelinked cysteine residues, and the reversible conversion from free thiolto disulfide can regulate specific enzyme activities (Ziegler, 1985).Furthermore, sulfide is electronegative and exhibits high affinity fortransition metals. Proteins containing transition metal atoms, such ascytochrome oxidase, can be profoundly affected by H₂S. And finally,metabolism of H₂S into other molecules containing reduced sulfurincreases the number of thiols that may exhibit specific biologicalactivity. In addition to (or perhaps because of) these potential modesof action, H₂S may exert effects on cardiopulmonary, neuroendocrine,immune, and/or hemostatic systems that ultimately prove beneficial ininjury and disease.

A U.S. provisional patent application entitled “Methods, compositionsand articles of manufacture for treating shock” filed on Apr. 20, 2006in the names of Mark B. Roth, Mike Morrison, and Eric Blackstonedescribes the treatment of shock and is hereby incorporated byreference.

B. Hypothermia

In yet another embodiment, the present inventor proposes use of thepresent invention to treat people with extreme hypothermia. The methodsand compositions of the present invention are useful for inducinghypothermia in a mammal in need of hypothermia. Hypothermia can be mild,moderate or profound. Mild hypothermia comprises achievement of a corebody temperature of approximately between 0.1 and 5 degrees Celsiusbelow the normal core body temperature of the mammal. The normal corebody temperature of a mammal is usually between 35 and 38 degreesCelsius. Moderate hypothermia comprises achievement of a core bodytemperature of approximately between 5 and 15 degrees Celsius below thenormal core body temperature of the mammal. Profound hypothermiacomprises achievement of a core body temperature of approximatelybetween 15 and 37 degrees Celsius below the normal core body temperatureof the mammal.

Mild hypothermia is known in the art to be therapeutically useful andeffective in both non-human mammals and in humans. The therapeuticbenefit of mild hypothermia has been observed in human clinical trialsin the context of out-of-hospital cardiac arrest. Exposure of humans tomild hypothermia in the context of cardiac arrest results in a survivaladvantage and an improved neurological outcome compared to standard ofcare with normothermia, or absence of mild hypothermia (Bernard et al.,2002; The Hypothermia After Cardiac Arrest Study Group et al. 2002).

Methods and compositions of the present invention may have advantagesover other methods known in the art, including, but not limited to,packing the subject in ice, or surrounding the subject with a “coolingtent” that circulates cool air or liquid, for inducing mild, moderate,or profound hypothermia in mammals or humans. In these cases, thesubject resists the reduction of core body temperature belownormothermia and tries to generate heat by shivering. Shivering, and thebody heat engendered therein, can have a negative impact on theachievement of mild hypothermia by, for example, slowing the rate ofdecrease in the core body temperature that is achieved using thestandard methods of hypothermia induction. Consequently, humanssubjected to therapeutic levels of hypothermia are also treated with adrug that inhibits shivering (by blocking neurotransmission at theneuromuscular junctions) (Bernard et al., 2002).

In a preferred embodiment, methods and compositions of the presentinvention are combined with invasive methods or medical devices known inthe art to induce therapeutic hypothermia in mammals or humans. Suchinvasive methods and devices include, but are not limited to, flexibleprobes or catheters that can be inserted into the vasculature of thesubject in need of hypothermia, wherein the temperature of the catheteris adjusted to below the normal body temperature of the subject,resulting in the cooling of blood which is in contact with the catheter.The cooled blood subsequently engenders a decrease in the core bodytemperature of the mammal. By incorporating feedback from a thermocouplemonitoring the core body temperature of the mammal, the temperature ofthe catheter can be modulated so as to maintain a pre-specified corebody temperature. Such medical devices for achieving and maintainingmild or moderate hypothermia, referred to in the art as endovasculartemperature therapy, are known in the art and are described for exampleon the World Wide Web at innercool.com and radiantmedical.com.

The method provides that patients with extreme hypothermia areadministered or exposed to an oxygen antagonist or other active compoundand then gradually restored to normal temperature while withdrawing, ina controlled fashion, the oxygen antagonist or other active compound. Inthis way, the oxygen antagonist or other active compound buffers thebiological systems within the subject so that they may be initiatedgradually without shock (or harm) to the subject.

In one embodiment, a subject suffering from hypothermia with be given anoral or intravenous dose of an oxygen antagonist or other activecompound. Intravenous provision may be preferred because of thepotential non-responsiveness of the subject and the ability to provide acontrolled dosage over a period of time. Alternatively, if available,the oxygen antagonist or other active compound may be provide in agaseous state, for example, using a mask for inhalation or even a sealedchamber that can house the entire subject.

Ideally, the patient will be stabilized in terms of heart rate,respiration and temperature prior to effecting any change. Once stable,the ambient environmental temperature will be increased, againgradually. This may be accomplished simply by removing the subject fromthe hypothermic conditions. A more regulated increase in temperature maybe effected by adding successive layers of clothing or blankets, by useof a thermal wrap with gradual increase in heat, or if possible, byplacing the subject in chamber whose temperature may be graduallyincreased.

It is preferred that the vital signs of the subject are monitored overthe course of the temperature increase. Also, in conjunction withincreasing the temperature, the oxygen antagonist or other activecompound is removed from the subject's environment. Both heat and oxygenantagonist (or other active compound) treatment are ceased at theappropriate endpoint, judged by the medical personnel monitoring thesituation, but in any event at the time the subject's temperature andother vital signs return to a normal range. Continued monitoringfollowing cessation of treatment is recommended for a period of at least24 hrs.

C. Hyperthermia

Under certain conditions, which can result from genetic, infectious,drug, or environmental causes, patients can loose homeostatictemperature regulation resulting in severe uncontrollable fever(hyperthermia). This can result in mortality or long-term morbidity,especially brain damage, if it is not controlled properly.

Mice inhaled H₂S at 80 ppm immediately underwent hibernation. Thisincluded an inability to regulate their body temperature when ambienttemperatures were dropped below room temperature. Accordingly, thistechnology could be used to control whole body temperature in certainstates of hyperthermia. This would likely involve administration of H₂S(or other oxygen antagonist or active compound) through inhalation orperfused into the blood supply to induce a hibernation state. It wouldbe useful to have the patient to be in stasis for between about 6 andabout 24 hours, during which time the source of the fever can beaddressed. In some embodiments of the invention, a patient is exposed toan oxygen antagonist or other active compound for about, at least about,or at most about 30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40,45, 50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24 hours, 1, 2, 3, 4, 5, 6, 7 days ormore, and any range or combination therein.

This can be combined with some whole-body temperature regulation (icebath/blanket/cooling system).

D. Cardioplegia and Coronary Heart Disease

In certain embodiments, the present invention may find use as solutionsfor the treatment of coronary heart disease (CHD) including a use forcardioplegia for cardiac bypass surgery (CABG).

CHD results from athlerosclerosis, a narrowing and hardening of thearteries that supply oxygen rich blood to the heart muscle. The arteriesharden and become narrow due to the buildup of plaque on the inner wallsor linings of the arteries. Blood flow to the heart is reduced as plaquenarrows the coronary arteries. This decreases the oxygen supply to theheart muscle. This may manifest in 1) angina, which is chest pain ordiscomfort that happens when the heart is not getting enough blood; 2)heart attack, which can occur when a blood clot suddenly cuts off mostor all blood supply to part of the heart and cells in the heart musclethat do not receive enough oxygen-carrying blood begin to die,potentially causing permanent damage to the heart muscle; 3) heartfailure, which is when the heart is unable to pump blood effectively tothe rest of the body; arrhythmias, which are changes in the normalrhythm of the heartbeats.

Since 1990, more people have died from CHD than any other cause. 3.8million men and 3.4 million women die each year from CHD. In 2002, over500,000 people in the United States alone died as a direct result ofheart disease. Despite improvements in survival rates, 1 in 4 men, and 1in 3 women in the U.S. still die within a year of a recognized firstheart attack.

Medical treatment of CHD includes medications to reduce the risk ofheart attack, heart failure and stroke, together with importantlifestyle changes to prevent the further build-up of fatty deposits inthe coronary arteries. Nonetheless, some type of surgical interventionis also frequently indicated.

About one-third of CHD patients will undergo coronary angioplasty andstenting. During balloon angioplasty, a balloon-tipped catheter isemployed to push plaque back against the arterial wall to allow forimproved blood flow in the artery. Coronary stenting often accompaniesthe angioplasty procedure. Stents are small wire-mesh metal tubes thatprovide scaffolding to support the damaged arterial wall, reducing thechance that the vessel will close again (restenosis) after angioplasty.In the United States, nearly one million balloon angioplasty proceduresare performed each year. Not all patients are able to be treated by thistechnique; such patients must undergo heart surgery. Michaels et al.,2002.

About 10% of CHD patients will undergo coronary artery bypass graft(CABG) surgery. Patients with severe narrowing or blockage of the leftmain coronary artery or those with disease involving two or threecoronary arteries are generally considered candidates for bypasssurgery. In CABG, the surgeon uses a portion of a healthy vessel (eitheran artery or a vein) from another part of the body to create a detour(or bypass) around the blocked portion of the coronary artery. Patientstypically receive from 1 to 5 bypasses in a given operation. During theprocedure, generally the heart is placed in a state of paralysis, knownas cardioplegia (CP), during which a heart-lung machine artificiallymaintains circulation. Patients are under general anesthesia during theoperation, which usually lasts between 3 to 6 hours.

Approximately 13% of all patients will be re-admitted to the hospitalwithin 30 days due to reasons related to the CABG. Hannan et al., 2003;Mehlhorn et al., 2001. One of the main reasons for re-admission is heartfailure, presumably due to ischemic damage during the surgery. Thus,much work is being done to improve the protection of the myocardiumduring the period when the heart is not being perfused normally.

Recent advances in cardiac surgery have centered upon optimization ofcardioplegic parameters in the hope of preventing postoperativeventricular dysfunction and improving overall outcome. Cohen et al.,1999.

Cardioplegic solutions are perfused through the vessels and chambers ofthe heart and cause its intrinsic beating to cease, while maintainingthe viability of the organ.

Cardioplegia (paralysis of the heart) is desirable during open-heartsurgery and during the procurement, transportation, and storage of donorhearts for use in heart transplantation procedures.

Early cardioplegic techniques employed cold crystalloid solutions toinitiate and maintain intraoperative cardiac arrest. However, it hasbecome clear that blood cardioplegia facilitated aerobic myocardialmetabolism during the cross-clamp period and reduced anaerobic lactateproduction. Furthermore, blood cardioplegia improves oxygen carryingcapacity, enhanced myocardial oxygen consumption and preservedmyocardial high-energy phosphate stores. Several different cardioplegicsolutions are available and different techniques for using cardioplegiasolutions are known in the art. For example, cardioplegic solutionsoften have varying amounts of potassium, magnesium, and several otherminor components. Sometimes drugs are added to the cardioplegic solutionto aid in muscle relaxation and protection from ischemia. Currentapproaches also include blood-only formulations with appropriateelectrolyte supplementation, such as glutamate-aspartate. Specificexamples of frequently used solutions are the St Thomas Hospitalsolution, University of Wisconsin Solution, Stanford Solution, and theBretschneider Solution. Examples of other emerging solutions involveadenosine, insulin or L-arginine containing solutions mentioned earlier.Varying the temperature at which the cardioplegic solution is used mayalso have beneficial effects.

A combination of continuous retrograde along with intermittent antegradecardioplegia reduces myocardial lactate production, preserved ATPstores, and improved metabolic recovery after cross-clamp release. Tepid(29° C.) cardioplegia reduces lactate and acid production duringcardioplegic arrest, and improves post-operative ventricular function.Cardioplegic flows of at least 200 mL/min are required to washoutdetrimental metabolic end-products and improve ventricular function. Itis abundantly clear now that future directions in cardioplegicmanagement will involve the use of cardioplegic additives to furtherimprove protective effects. For example, attempts have been made toharness the beneficial effects of ischemic pre-conditioning usingadenosine. Similarly, insulin cardiopolegia has been employed in orderto enhance ventricular performance by stimulating early postoperativeaerobic metabolism. Finally, L-arginine, a nitric oxide donor has beendemonstrated to be beneficial in experimental studies and may representa further option for the enhancement of intraoperative myocardialprotection. Future benefit of cardioplegic supplementation is likely tobe observed in high-risk with poor ventricular function, for whichcurrent protective techniques are inadequate. There is a steady increasein the incidence of high-risk patients presenting, and these cases, andconsequent complications, place a disproportionate burden on the healthcare system. Thus, improvements in this area hold great promise for theadvancement of care in this field.

Despite the protective effects provided by the current methods forinducing cardioplegia, there is still some degree ofischemic-reperfusion injury to the myocardium. Ischemic-reperfusioninjury during cardiac bypass surgery results in poor outcomes (bothmorbidity and mortality), especially due to an already weakened state ofthe heart. Myocardial ischemia results in anaerobic myocardialmetabolism. The end products of anaerobic metabolism rapidly lead toacidosis, mitochondrial dysfunction, and myocyte necrosis. High-energyphosphate depletion occurs almost immediately, with a 50 percent loss ofATP stores within 10 minutes. Reduced contractility occurs within 1 to 2minutes, with development of ischemic contracture and irreversibleinjury after 30 to 40 minutes of normothermic (37° C.) ischemia.

Reperfusion injury is a well-known phenomenon following restoration ofcoronary circulation. Reperfusion injury is characterized by abnormalmyocardial oxidative metabolism. In addition to structural changescreated during ischemia, reperfusion may produce cytotoxic oxygen freeradicals. These oxygen free radicals play a significant role in thepathogenesis of reperfusion injury by oxidizing sarcolemmalphospholipids and thus disrupting membrane integrity. Oxidized freefatty acids are released into the coronary venous blood and are a markerof myocardial membrane phospholipid peroxidation. Protamine inducescomplement activation, which activates neutrophils. Activatedneutrophils and other leukocytes are an additional source of oxygen freeradicals and other cytotoxic substances.

The present invention provides methods and compositions for inducingcardioplegia that will provide greater protection to the heart duringbypass surgery. In certain embodiments, the present invention provides acardioplegic solution comprising H₂S (or another active compound)dissolved in solution or bubbled as a gas in the solution. In someembodiments, the invention further comprises at least a first device,such as a catheter or cannula, for introducing an appropriate dose ofthe cardioplegic solution to the heart. In certain aspects, theinvention further comprises at least a second device, such as a catheteror cannula, for removing the cardioplegic solution from the heart.

Bypass surgery typically last for 3-6 hours, however, complications andmultiple vessel CABG can extend the duration to 12 hours or longer. Itis contemplated that the heart would be kept in stasis during thesurgery. Thus, in some embodiments of the invention, the heart isexposed to an oxygen antagonist or other active compound for about, atleast about, or at most about 30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25,30, 35, 40, 45, 50, 55 minutes, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16, 17, 18 hours or more, and any range or combinationtherein.

E. Reducing Damage from Cancer Therapy

Cancer is a leading cause of mortality in industrialized countriesaround the world. The most conventional approach to the treatment ofcancer is by administering a cytotoxic agent to the cancer patient (ortreatment ex vivo of a tissue) such that the agent has a more lethaleffect on the cancer cells than normal cells. The higher the dose or themore lethal the agent, the more effective it will be; however, by thesame token, such agents are all that more toxic (and sometimes lethal)to normal cells. Hence, chemo- and radiotherapy are often characterizedby severe side effects, some of which are life threatening, e.g., soresin the mouth, difficulty swallowing, dry mouth, nausea, diarrhea,vomiting, fatigue, bleeding, hair loss and infection, skin irritationand loss of energy (Curran, 1998; Brizel, 1998).

Recent studies suggest that transient and reversible lowering of thecore body temperature, or “hypothermia,” may lead to improvements in thefight against cancer. Hypothermia of 28° C. was recently found to reduceradiation, doxorubicin- and cisplatin-induced toxicity in mice. Thecancer fighting activity of these drugs/treatments was not compromisedwhen administered to cooled animals; rather, it was enhanced,particularly for cisplatin (Lundgren-Eriksson et al., 2001). Based onthis and other published work, the inventor proposes a further reductionin core temperature will provide benefit to cancer patients. Thus, thepresent invention contemplates the use of oxygen antagonists or otheractive stasis compound to induce stasis in normal tissues of a cancerpatient, thereby reducing the potential impact of chemo- or radiotherapyon those tissues. It also permits the use of higher doses of chemo- andradiotherapy, thereby increasing the anti-cancer effects of thesetreatments.

Treatment of virtually any hyperproliferative disorder, including benignand malignant neoplasias, non-neoplastic hyperproliferative conditions,pre-neoplastic conditions, and precancerous lesions, is contemplated.Such disorders include restenosis, cancer, multi-drug resistant cancer,primary psoriasis and metastatic tumors, angiogenesis, rheumatoidarthritis, inflammatory bowel disease, psoriasis, eczema, and secondarycataracts, as well as oral hairy leukoplasia, bronchial dysplasia,carcinomas in situ, and intraepithelial hyperplasia. In particular, thepresent invention is directed at the treatment of human cancersincluding cancers of the prostate, lung, brain, skin, liver, breast,lymphoid system, stomach, testicles, ovaries, pancreas, bone, bonemarrow, gastrointestine, head and neck, cervix, esophagus, eye, gallbladder, kidney, adrenal glands, heart, colon and blood. Cancersinvolving epithelial and endothelial cells are also contemplated fortreatment.

Generally, chemo- and radiotherapy are designed to reduce tumor size,reduce tumor cell growth, induce apoptosis in tumor cells, reduce tumorvasculature, reduce or prevent metastasis, reduce tumor growth rate,accelerate tumor cell death, and kill tumor cells. The goals of thepresent invention are no different. Thus, it is contemplated that onewill combine oxygen antagonist (or other active compound) compositionsof the present invention with secondary anti-cancer agents (secondaryagents) effective in the treatment of hyperproliferative disease. An“anti-cancer” agent is capable of negatively affecting cancer in asubject, for example, by killing cancer cells, inducing apoptosis incancer cells, reducing the growth rate of cancer cells, reducing theincidence or number of metastases, reducing tumor size, inhibiting tumorgrowth, reducing the blood supply to a tumor or cancer cells, promotingan immune response against cancer cells or a tumor, preventing orinhibiting the progression of cancer, or increasing the lifespan of asubject with cancer.

Secondary anti-cancer agents include biological agents (biotherapy),chemotherapy agents, and radiotherapy agents. More generally, theseother compositions are provided in a combined amount effective to killor inhibit proliferation of the cancer or tumor cells, while at the sametime reducing or minimizing the impact of the secondary agents on normalcells. This process may involve contacting or exposing the cells with anoxygen antagonist (or other active compound) and the secondary agent(s)at the same time. This may be achieved by contacting the cell with asingle composition or pharmacological formulation that includes bothagents, or by contacting or exposing the cell with two distinctcompositions or formulations, at the same time, wherein one compositionincludes an oxygen antagonist and the other includes the secondagent(s).

Alternatively, the oxygen antagonist (or other active compound) therapymay precede or follow the secondary agent treatment by intervals rangingfrom minutes to weeks. In embodiments where the other agent andexpression construct are applied separately to the cell, one wouldgenerally ensure that a significant period of time did not expirebetween the time of each delivery, such that the agent and expressionconstruct would still be able to exert an advantageously combined effecton the cell. In such instances, it is contemplated that one may contactthe cell with both modalities within about 12-24 h of each other and,more preferably, within about 6-12 h of each other. In some situations,it may be desirable to extend the time period for treatmentsignificantly, however, where several days (2, 3, 4, 5, 6 or 7) toseveral weeks (1, 2, 3, 4, 5, 6, 7 or 8) lapse between the respectiveadministrations. In certain embodiments, it is envisioned thatbiological matter will be kept in stasis for between about 2 and about 4hours while the cancer treatment is being administered. In someembodiments of the invention, biological matter is exposed to an oxygenantagonist or other active compound for about, at least about, or atmost about 30 seconds, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45,50, 55 minutes, 1, 2, 3, 4, 5, 6 hours or more, and any range orcombination therein.

Various combinations may be employed; the active compound is “A” and thesecondary anti-cancer agent, such as radio- or chemotherapy, is “B”:

A/B/A B/A/B B/B/A A/A/B A/B/B B/A/A A/B/B/B B/A/B/B B/B/B/A B/B/A/BA/A/B/B A/B/A/B A/B/B/A B/B/A/A B/A/B/A B/A/A/B A/A/A/B B/A/A/A A/B/A/AA/A/B/A

Administration of the oxygen antagonists or other active compounds ofthe present invention to a patient will follow general protocols for theadministration of chemotherapeutics, taking into account the toxicity,if any, of the compound. It is expected that the treatment cycles wouldbe repeated as necessary. It also is contemplated that various standardtherapies, as well as surgical intervention, may be applied incombination with the above-described anti-cancer therapy. It is furthercontemplated that any combination treatment contemplated for use with anactive compound and a non-active compound (such as chemotherapy), may beapplied with respect to multiple active compounds.

1. Chemotherapy

Cancer therapies also include a variety of combination therapies withboth chemical and radiation based treatments. Combination chemotherapiesinclude, for example, cisplatin (CDDP), carboplatin, procarbazine,mechlorethamine, cyclophosphamide, camptothecin, ifosfamide, melphalan,chlorambucil, busulfan, nitrosurea, dactinomycin, daunorubicin,doxorubicin, bleomycin, plicomycin, mitomycin, etoposide (VP16),tamoxifen, raloxifene, estrogen receptor binding agents, taxol,gemcitabien, navelbine, farnesyl-protein transferase inhibitors,transplatinum, 5-fluorouracil, vincristine, vinblastine andmethotrexate, Temazolomide (an aqueous form of DTIC), or any analog orderivative variant of the foregoing. The combination of chemotherapywith biological therapy is known as biochemotherapy.

2. Radiotherapy

Other factors that cause DNA damage and have been used extensivelyinclude what are commonly known as γ-rays, X-rays, and/or the directeddelivery of radioisotopes to tumor cells. Other forms of DNA damagingfactors are also contemplated such as microwaves and UV-irradiation. Itis most likely that all of these factors effect a broad range of damageon DNA, on the precursors of DNA, on the replication and repair of DNA,and on the assembly and maintenance of chromosomes. Dosage ranges forX-rays range from daily doses of 50 to 200 roentgens for prolongedperiods of time (3 to 4 wk), to single doses of 2000 to 6000 roentgens.Dosage ranges for radioisotopes vary widely, and depend on the half-lifeof the isotope, the strength and type of radiation emitted, and theuptake by the neoplastic cells.

The terms “contacted” and “exposed,” when applied to a cell, are usedherein to describe the process by which a composition of the invention(for example, a hypoxic antitumor compound) or a chemotherapeutic orradiotherapeutic agent is delivered to a target cell or are placed indirect juxtaposition with the target cell. In combination therapy, toachieve cell killing or stasis, both agents may be delivered to a cellin a combined amount effective to kill the cell or prevent it fromdividing.

J. Immunotherapy

Immunotherapeutics, generally, rely on the use of immune effector cellsand molecules to target and destroy cancer cells. The immune effectormay be, for example, an antibody specific for some marker on the surfaceof a tumor cell. The antibody alone may serve as an effector of therapyor it may recruit other cells to actually effect cell killing. Theantibody also may be conjugated to a drug or toxin (chemotherapeutic,radionuclide, ricin A chain, cholera toxin, pertussis toxin, etc.) andserve merely as a targeting agent. Alternatively, the effector may be alymphocyte carrying a surface molecule that interacts, either directlyor indirectly, with a tumor cell target. Various effector cells includecytotoxic T cells and NK cells.

Immunotherapy could also be used as part of a combined therapy. Thegeneral approach for combined therapy is discussed below. In one aspectof immunotherapy, the tumor cell must bear some marker that is amenableto targeting, i.e., is not present on the majority of other cells. Manytumor markers exist and any of these may be suitable for targeting inthe context of the present invention. Common tumor markers includecarcinoembryonic antigen, prostate specific antigen, urinary tumorassociated antigen, fetal antigen, tyrosinase (p97), gp68, TAG-72, HMFG,Sialyl Lewis Antigen, MucA, MucB, PLAP, estrogen receptor, lamininreceptor, erb B and p155. An alternative aspect of immunotherapy is toanticancer effects with immune stimulatory effects. Immune stimulatingmolecules also exist including: cytokines such as IL-2, IL-4, IL-12,GM-CSF, gamma-IFN, chemokines such as MIP-1, MCP-1, IL-8 and growthfactors such as FLT3 ligand. Combining immune stimulating molecules,either as proteins or using gene delivery in combination with a tumorsuppressor such as mda-7 has been shown to enhance anti-tumor effects(Ju et al., 2000)

As discussed earlier, examples of immunotherapies currently underinvestigation or in use are immune adjuvants (e.g., Mycobacterium bovis,Plasmodium falciparum, dinitrochlorobenzene and aromatic compounds)(U.S. Pat. No. 5,801,005; U.S. Pat. No. 5,739,169; Hui and Hashimoto,1998; Christodoulides et al., 1998), cytokine therapy (e.g., interferonsα, β and γ; IL-1, GM-CSF and TNF) (Bukowski et al., 1998; Davidson etal., 1998; Hellstrand et al., 1998) gene therapy (e.g., TNF, IL-1, IL-2,p53) (Qin et al., 1998; Austin-Ward and Villaseca, 1998; U.S. Pat. No.5,830,880 and U.S. Pat. No. 5,846,945) and monoclonal antibodies (e.g.,anti-ganglioside GM2, anti-HER-2, anti-p185) (Pietras et al., 1998;Hanibuchi et al., 1998). Herceptin (trastuzumab) is a chimeric(mouse-human) monoclonal antibody that blocks the HER2-neu receptor. Itpossesses anti-tumor activity and has been approved for use in thetreatment of malignant tumors (Dillman, 1999). Combination therapy ofcancer with herceptin and chemotherapy has been shown to be moreeffective than the individual therapies. Thus, it is contemplated thatone or more anti-cancer therapies may be employed with the anti-tumortherapies described herein.

F. Neurodegeneration

The present invention may be used to treat neurodegenerative diseases.Neurodegenerative diseases are characterized by degeneration of neuronaltissue, and are often accompanied by loss of memory, loss of motorfunction, and dementia. With dementing diseases, intellectual and higherintegrative cognitive faculties become more and more impaired over time.It is estimated that approximately 15% of people 65 years or older aremildly to moderately demented. Neurodegenerative diseases includeParkinson's disease; primary neurodegenerative disease; Huntington'sChorea; stroke and other hypoxic or ischemic processes; neurotrauma;metabolically induced neurological damage; sequelae from cerebralseizures; hemorrhagic shock; secondary neurodegenerative disease(metabolic or toxic); Alzheimer's disease, other memory disorders; orvascular dementia, multi-infarct dementia, Lewy body dementia, orneurodegenerative dementia.

Evidence shows that the health of an organism, and especially thenervous system, is dependent upon cycling between oxidative andreductive states, which are intimately linked to circadian rhythms. Thatis, oxidative stress placed upon the body during consciousness is cycledto a reductive environment during sleep. This is thought to be a largepart of why sleep is so important to health. Certain neurodegenerativedisease states, such as Huntington's disease and Alzheimer's disease, aswell as the normal processes of aging have been linked to a discord inthis cycling pattern. There is also some evidence that brain H₂S levelsare reduced in these conditions (Eto et al., 2002).

The present invention can be used to regulate and control the cyclingbetween the oxidative and reduced states, for example, to prevent orreverse the effects of neurodegenerative diseases and processes.Controlling circadian rhythms can have other applications, for example,to adjust these cycling patterns after traveling from one time zone toanother, so as to adjust to the new time zone. Furthermore, reducedmetabolic activity overall has been shown to correlate with health inaged animals and humans. Therefore, the present invention would also beuseful to suppress overall metabolic function to increase longevity andhealth in old age. It is contemplated that this type of treatment wouldlikely be administered at night, during sleep for period ofapproximately 6 to 10 hours each day. This could require daily treatmentfor extended periods of time from months to years.

G. Aging

Furthermore, in certain states of stasis, including but not limited tostates where the biological matter is in a state of suspended animation,aging itself may be thoroughly or completely inhibited for the period oftime when the biological matter is in that state. Thus the presentinvention may inhibit aging of biological material, with respect toextending the amount of time the biological material would normallysurvive and/or with respect to progression from one developmental stageof life to another.

H. Blood Disease

A number of blood diseases and conditions may be addressed usingcompositions and methods of the invention. These diseases include, butare not limited to, thalassemia and sickle cell anemia.

1. Thalassemia

Normal hemoglobin contains two alpha and two beta globin polypeptide(protein) chains, each bound to an iron containing heme ring.Thalassemia is a group of conditions in which there is an imbalance ofalpha and beta chains leading to the unpaired chains precipitating onthe normally fragile red blood cell membrane, leading to celldestruction. This leads to severe anemia that the marrow tries tocompensate for by trying to make more red cells. Unfortunately due totoxicity from unpaired chains this process is very inefficient leadingto massive expansion of the marrow space and spread of blood making toother parts of the body. This and the anemia lead to major toxicities.Several models exist as to why unpaired globin chains are so damagingbut many entail that increased free radicals generated by the ironattached to the unpaired globin chains are central to the earlydestruction of the red cells. Thus any intervention that might decreasethe oxidative damage from these free radicals could increase red celllifespan, improve the anemia, lead to decreased need for making redcells, and less damage from marrow expansion and spread.

It is estimated that over 30,000 children are born with severethalassemia each year, of which it is estimated that most living indeveloped countries live into their twenties, while in third worldcountries (where the majority of patients live) most die as youngchildren. Based on the current results in other model systems presentedhere, it expected that exposing animals with thalassemia to sulfideswill increase their red cells' ability to withstand oxidative damage,leading to prolonged red cell survival.

2. Sickle Cell Disease

Normal hemoglobin (HbA) contains two alpha and two beta globinpolypeptide (protein) chains, each bound to an iron containing hemering. In sickle cell disease (SCD; also called sickle cell anemia) is agroup of conditions in which a mutant beta chain leads to an alteredhemoglobin (HbS). Upon deoxygention HbS can polymerize (crystallize) andprecipitate damaging the normally fragile red blood cell membrane,leading to cell destruction and anemia low red blood cells (RBC). Inaddition cells with polymerized HbS change shape (sickle) and becomesticky and activate mechanisms leading to coagulation and blockage ofblood flow. This can lead to hypoxic damage of the surrounding tissueresulting in pain, organ dysfunction and eventually premature death.Decreased stores of sulfur containing antioxidants are noted inpatients. In addition oxidative damage and increased reactive oxygenspecies (ROS) have been implicated in crystallization, RBC membranedamage and tissue damage related to inadequate blood flow. Sulfides havebeen implicated in “re-charging” antioxidant stores, and potentiallyminimizing oxidative damage. There are reasons to think sulfides couldprevent problems at several stages of sickle cell pathology.Furthermore, given the ability of oxygen antagonists to protect fromhypoxia in other systems, suggests that it should also protect animalsand humans subjected to the adverse conditions posed by this diseasestate.

Over 120,000 children are born with SCD each year. Patients in developedcountries now live into their 40's and 50's however with tremendousproblems with pain and organ damage including stroke, lung, heart andskin problems. In third world countries (where the majority of patientslive) most die as young children. Our hypothesis is that exposinganimals and eventually humans with SCD to sulfides will result in healthimprovements.

IV. Preservation Applications

The present invention can be used to preserve or store a variety ofbiological matter, including cells, tissues, organs, and whole organismsfor transport and/or storage purposes. In certain embodiments, thebiological matter is preserved so as to prevent damage from adverseconditions.

In embodiments of the invention, biological matter can be exposed to anactive compound for about, at least about, or at most about 30 seconds,1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 minutes, 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24 hours, 1, 2, 3, 4, 5, 6, 7 days, 1, 2, 3, 4, 5 weeks, 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12 months, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16, 17, 18, 19, 20 or more years, and any combination orrange derivable therein. It is contemplated that active compounds may beused to induce stasis and that other agents may be used to maintainstasis and preserve them for any significant period of time.Alternatively, it is contemplated that an active compound may be used toinduce and/or maintain stasis. This may be in combination with otheragents, such environmental changes in pressure and/or temperature.

1. Cells

As discussed above, a variety of cells are contemplated for use with thepresent invention. It is contemplated that such cells can be preservedin methods, apparatuses, and compositions of the invention.

a. Platelets

In certain embodiments, the present invention may find use in thepreservation of platelets. Platelets are small cell fragments (˜⅓ sizeof erythrocytes) that play a vital role in the formation of blood clotsat the site of bleeding. Hemostasis is achieved by adherence to thewalls of blood vessels, release of coagulating chemicals, forming bloodclots to plug the rupture in the vascular wall and/or narrowed bloodvessels. Normal platelet counts are between 150,000-400,000 counts/μL.Platelet concentrates are transfused for a variety of indications, forexample: 1) to prevent bleeding due to thrombocytopenia; 2) in ableeding patient to maintain a platelet count above 50,000; 3) toaddress abnormal platelet function that is congenital or due tomedications, sepsis, malignancy, tissue trauma, obstetricalcomplications, extra corporeal circulation, or organ failure such asliver or kidney disease.

Each unit of platelets contains an average of 0.8−0.85×10¹¹ platelets.Platelet concentrates also contain about 60 mL of plasma (coagulationfactors) and small numbers of red blood cells and leukocytes. Plateletunits must be maintained at room temperature (20° C.-24° C.) andagitated during storage. They can be stored at the Blood Center for upto 5 days. Longer storage is not possible at present due todeterioration of the platelets, and the risk of microbial contamination.Two sources of platelets currently exist:

1) Pooled random donor platelet concentrates are prepared from plateletsthat have been harvested by centrifuging units of whole blood. Up to 8units of platelets, each from a separate donor, can be pooled into asingle bag for transfusion. Platelets expire 4 hours after pooling. Allunits are from the same ABO type. If ABO compatible platelets areunavailable, ABO incompatible platelets can be substituted with verylittle risk. The usual adult dose is 4-6 units of pooled random donorplatelets.

2) Apheresis platelets, collected from a single donor, are prepared instandard (equivalent to ˜4 pooled units) and “large” (equivalent to 6pooled units) sizes. An apheresis platelet concentrate contains 200-400mL of plasma. They may be collected as a random unit (random apheresisplatelets) or be obtained for a specific recipient from a family memberor a volunteer HLA compatible “directed” donor. Apheresis plateletsexpire 4 hours after processing for release from the blood center.

Platelet storage poses problems that are not found with the storage ofwhole blood or other components. While whole blood, red and white cellsmay be stored at 4° C. for weeks, platelets will aggregate in coldstorage and when allowed to settle. Therefore, the standard method ofstoring platelets is at room temperature, approximately 20 to 24° C.,with gentle agitation. Even under these conditions, platelets can onlybe stored for 5 days before they need to be discarded. This problem ofoutdating results in approximately $500 million annually in lost revenuefor US hospitals. If even a moderate increase in shelf life could beattained, approximately 90% of this loss could be avoided.

An additional problem with platelet storage is bacterial contamination.Contamination is primarily due to staphylococci from the skin during thephlebotomy, or else donor bacteremia. The bacterial contamination ofplatelets represents the largest infectious risk with any bloodtransfusion procedure.

A significant factor affecting the viability of platelets is regulationof pH. Virtually all units of platelets stored according to thecurrently accepted methods show a decrease in pH from their initialvalue of approximately 7.0. This decrease is primarily due to theproduction of lactic acid by platelet glycolysis and to a lesser extentto accumulation of CO₂ from oxidative phosphorylation. As the pH falls,the platelets change shape from discs to spheres. If the pH falls below6.0, irreversible changes in platelet morphology and physiology renderthem non-viable after transfusion. An important goal in plateletpreservation, therefore, is to prevent this decrease in pH. It waspreviously thought that platelets must be stored in a containerpermeable to oxygen since glycolysis is stimulated when oxygenavailability is limited (see e.g., U.S. Pat. No. 5,569,579). The presentinvention, however, demonstrates that the viability of stored plateletscan be extended by storing them in an anoxic environment.

The present invention provides methods and compositions that increasethe survival time of stored platelets and reduce bacterialcontamination. In one embodiment, the present invention provides asealable, oxygen-impermeable container into which the platelets areplaced. After sealing, an anaerobic generator (e.g., a sodiumborohydride tablet with a palladium catalyst) converts the atmosphericoxygen in the container to water. The container can also contain anindicator, which indicates the level of oxygen tension. Once in anoxicconditions, the platelets can also be stored at lower temperatures.

The platelets may be suspended and stored in plasma or any plateletstorage solution known in the art. For example, U.S. Pat. Nos. 4,828,976and 4,447,415 disclose several commonly used solutions suitable for thestorage of platelets.

Typically, platelets are stored in plasma from the donor andadministered in that form.

Generally, the invention consists of a sealed environment (container,jar, impermeable bag, or chamber) in which the oxygen tension can bereduced to less than 1% (10,000 ppm) and more specifically in the rangeof 10-100 ppm, or less. The reduction in atmospheric oxygen in thisenvironment can be achieved by a number of methods known in the art. Forexample, the reduction in atmospheric oxygen can be achieved with thegeneration of hydrogen gas, with or without a catalyst, to combine withthe oxygen to produce water. Other reactions could be catalyzed tocombine the oxygen with other compounds, such as carbon to producecarbon dioxide, and so on. Also, the oxygen could be replaced byexchanging all the air in the chamber with gas containing anycombination of gases that do not include oxygen. Also, the oxygen couldbe removed by placing the chamber under vacuum, to remove all gases.Alternatively, the oxygen could be competed by using another gas orcompound that competes for oxygen, such as CO. A combination of removalof oxygen and competition of remaining oxygen could also be used. Thedevice may also comprise a way to measure the concentration of oxygen toensure the appropriate anaerobic state has been achieved. For example,oxygen concentration can be measured using an anaerobic indicator basedon methlyene blue that changes from blue color to colorless in theabsence of oxygen. Alternatively, an oxygen meter or other oxygenmeasuring device could be used.

The device also comprises some way to contain the platelets in thesealed environment such that the oxygen can be removed from the solutioncontaining the platelets, as well as from the platelets themselves. Anexample of this is to have the platelets in a gas-permeable bag placedinside the sealed environment. The platelets could also be held in anopen container inside the sealed environment. Alternatively, theplatelets could be placed directly in the impermeable, sealedcontainer/bag.

The Bio-Bag™ from Becton Dickinson (product number 261215) is oneexample of a sealable, oxygen-impermeable container that can be used tocreate an anoxic environment for the storage of platelets. The Bio-Bag,which is a kit sold for the isolation of anaerobic bacteria, includes asealable, gas-impermeable bag; an anaerobic indicator; an anaerobicgenerator (hydrogen gas generator); and palladium catalysts. Theplatelets in a gas-permeable bag, would be sealed inside of the Bio-Bagfor storage.

The anaerobic generator in the Bio-Bag is a device activated by theaddition of water, which passes through a series of channels to a filterpaper wick. The wick delays and regulates the introduction of water intothe tablet chamber, providing a controlled release of the hydrogen gas.The gas-generating tablet consists of sodium borohydride. The hydrogenreleased from this reaction, combines with the atmospheric oxygen in thesealed container to produce water. This reaction is catalyzed by thepalladium in the container.

The Puget Sound Blood Center (PSBC) independently assessed the state ofthe platelets stored in anoxic conditions on days 0, 5 and 8 using astandardized panel of in vitro tests. Results indicated that plateletsstored in anoxic conditions for up to 8 days perform as good, or betterthan, platelets stored under standard conditions. Ongoing studies arereplicating this experiment, and extending the observation time to 13days.

Those of skill in the art will be familiar with methods for assayingplatelet function. For example, as described in U.S. Pat. No. 6,790,603,platelet function can be assayed by (1) internal protein expression onthe cell membrane in response to challenge with an activation-inducingagonist; (2) ability to aggregate when challenged by an agonist; and (3)adenosine triphosphate secretion. Examples of agonist that can causeactivation of platelet function include thrombin, epinephrine, ADP andcollagen.

Internal protein expression may be measured by conjugation of a moleculewith a fluorescent dye, followed by sorting in a fluorescent cellsorter. In general, it is preferable to use two monoclonal antibodies,one that binds a cell surface molecule that is constitutively expressedand a second that binds a cell surface molecule that is expressed onlyafter activation. Each monoclonal antibody is conjugated to a differentcolored dye, that can be distinguished by spectrofluorometry. Anon-limiting example of a constitutively expressed cell surface moleculeis GPIbIIIa; a non-limiting example of a cell surface molecule expressedafter activation is P-selectin. It is well know in the art to makemonoclonal antibodies to proteins. U.S. Pat. No. 5,470,738, is oneexample of a method of making monoclonal antibodies to GPIIIa. Anotheranti-platelet monoclonal antibody is that to GP IV, as disclosed by U.S.Pat. No. 5,231,025. Antibodies can also be purchased commercially fromsuch companies as Becton-Dickinson (Philadelphia).

Another parameter of platelet function is the ability to aggregate whenchallenged by an agonist. The platelet suspension is dense and milkywhite. Aggregation and subsequent settling of the aggregates can beestimated visually, or measured with a densitometer.

Yet another measure of platelet function is the secretion of ATP.Platelets that are able to function well are able to secrete ATP whilecells that have already been activated or have lost function in otherways cannot secrete ATP.

2. Cell Culture

The present invention can be extended to protecting cells in culture,which might otherwise die or be induced into apoptosis. In the contextof the present invention, cells are exposed to an active compound priorto and/or while in culture. Cells that can be cultured according to theinvention include those that can eventually be placed back into aphysiological context, i.e., those for subsequent transplant. Such cellsinclude, but are not limited to, bone marrow, skin cells and epithelialcells. Also, some transplantable cells would greatly benefit fromexpansion in culture, thereby increasing the amount of material that canbe introduced into the host. Epithelial cells from the gastrointestinaltract are specifically contemplated as cells that can benefit fromexposure to an active compound.

Furthermore, the invention extends to the culture of tumor cells.Culture of tumor cells is known to result in alteration of thephenotype, and in some cases death. This makes tissue cultureexperiments on tumor cells highly unpredictable.

General cell culture techniques are well known to those of skill in theart. Examples of this knowledge can be found in Shaw (1996) and Davis(1994), both of which are incorporated by reference herein. Generalinformation and modifications of traditional cell culture techniques isalso found in U.S. Pat. No. 5,580,781, which is incorporated byreference. Furthermore, techniques for culturing skin cells aredescribed in U.S. Pat. No. 6,057,148, which is incorporated byreference. It is contemplated that these techniques, as well as othersknown to those of skill in the art, will be supplemented with mediacontaining one or more active compounds, or perfused with an activecompound as liquids and/or gases.

E. Preservation of Cells, Tissue and Organs

In certain embodiments of the invention, it is desirable to preservebiological matter, so as to prevent as much as possible damage to thematter from perishing or decomposing. Though the first successful kidneytransplant was performed in 1954 and the first heart and livertransplants were conducted in 1967, every year, thousands of people diein need of an organ transplant. Due to a variety of causes, they needhearts, lungs, kidneys, and livers. In addition, there are patients whocould use a pancreas or a cornea. While there is a constant need fororgan donors, another significant hurdle in providing those in need ofan organ transplant with an organ is the limitations in current organpreservation techniques. For example, it is widely believed that a humanheart must be transported within four hours for there to be any chanceof the subsequent transplantation to be a success. Rager, 2004 (seetable below).

Maximum cold ischemic time Organ Preservation Time Heart and Lungs  4-6hours Liver 12-24 hours Kidney 48-72 hours Pancreas 12-24 hours SmallIntestine   12 hoursMoreover, the primary cause of organ transplant failure for transplantedhearts in the first 30 days is ischemic-reperfusion injury.

Organ procurement and preservation, tissue matching, andimmunosuppression are the principal ingredients for successful solidorgan transplantation. The technical aspects of the organ procurementoperation allow multiple teams to work together to procure all usefulorgans form a single donor. On average, 3.6 organs are procured from asingle deceased donor.

Preserving solid organs depends on rapid intravascular cooling done insitu, followed by removal of the organs, storage of the organs inice-cold preservation fluid and rapid transport to the recipients'hospitals. The cold ischemic time is the length of time the organs areon ice, without blood flow. The maximum cold ischemic time limits theamount of time that can pass between organ recovery and the organtransplant (Table 5). Between 2%-10% of matched and procured organscannot be used due to extended ischemic time, depending on the type oforgan. Similarly, approximately 10 to 20% of procured organs are notused due to poor organ function and/or infection (not includingHIV/CMV/hepatitis).

Current preservation techniques involve the use of ice-cold solutionsthat include electrolytes, antioxidants, hydrogen ion buffers andsugars. Punch et al., 2001. Appropriate tissue matching depends on bloodgroup matching (e.g., blood type, A, B or O) for all organs.Immunosuppresive regimens typically include three drugs: aglucocorticoid such as prednisone, an antimetabolite such as azathiprineor mycophenolate, and a calcineurin inhibitor such as cyclosporine ortacrolimus.

The two most frequently used methods for preserving/transporting heartsfor transplantation are hypothermic storage and continuous perfusion. Inthe former method, the heart is arrested, removed from the donor, andthen rapidly cooled and transported in cold storage. In the lattermethod, the following steps are typically employed: 1) pulsatile flow;2) hypothermia; 3) membrane oxygenation, and 4) a perfusate containingboth.

To improve the prospect of a successful transplant, techniques forbetter preserving an organ for transplantation have been developed. Twogeneral areas of development have occurred, one in the area ofpreservation solutions and the other in the area of organ containers.

In certain contexts, such as transplant, adverse consequences of woundhealing may impair or prevent proper engraftment of transplanted tissue.In the context of the present invention, it is envisioned that donatedand recipient tissues will be treated pre-transplantation with an oxygenantagonist or other active compound, as discussed above with respect towound healing, in an effort to inhibit biological processes such asinflammation, apoptosis and other wound healing/post-transplantationevents that damage engrafted tissues.

F. Organisms

Such organisms could be used for research purposes, such as laboratorymice (mouse banking), or for consumption, such as fish. In thesesituation, it is contemplated that stasis can be maintainedindefinitely. Moreover, stasis can be induced in plants or parts ofplants, including fruit, flowers, leaves, stems, seeds, cuttings. Plantscan be agricultural, medicinal, or decorative. Induction of stasis inplants may enhance the shelf life or pathogen resistance of the whole orpart of the plant. Thus, in embodiments of the invention, an organism orpart thereof can be exposed to an oxygen antagonist or other activecompound for about, at least about, or at most about 30 seconds, 1, 2,3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 minutes, 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24hours, 1, 2, 3, 4, 5, 6, 7 days, 1, 2, 3, 4, 5 weeks, 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12 months, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, 16, 17, 18, 19, 20 or more years, and any combination or rangederivable therein.

G. Preservation Agents

A variety of preservation solutions have been disclosed in which theorgan is surrounded or perfused with the preservation solution while itis transported. One of the most commonly used solution is ViaSpan®(Belzer UW), which employed with cold storage. Other examples of suchsolutions or components of such solutions include the St. Thomassolution (Ledingham et al., J. Thorac. Cardiobasc. Surg. 93:240-246,1987), Broussais solution, UW solution (Ledingham et al., Circulation 82(Part 2) IV351-8, 1990), Celsior solution (Menasche et al., Eur. J.Cardio. Thorax. Surg. 8:207-213, 1994), Stanford University solution,and solution B20 (Bernard et al., J. Thorac. Cardiovasc. Surg.90:235-242, 1985), as well as those described and/or claimed in U.S.Pat. Nos. 6,524,785; 6,492,103; 6,365,338; 6,054,261; 5,719,174;5,693,462; 5,599,659; 5,552,267; 5,405,742; 5,370,989; 5,066,578;4,938,961; and, 4,798,824.

In addition to solutions, other types of materials are also known foruse in transporting organs and tissue. These include gelatinous or othersemi-solid material, such as those described, for example, in U.S. Pat.No. 5,736,397.

Some of the systems and solutions for organ preservation specificallyinvolve oxygen perfusion in the solution or system to expose the organto oxygen because it is believed that maintaining the organ or tissue inan oxygenated environment improves viability. See Kuroda et al.,(Transplantation 46(3):457-460, 1988) and U.S. Pat. Nos. 6,490,880;6,046,046; 5,476,763; 5,285,657; 3,995,444; 3,881,990; and, 3,777,507.Isolated hearts that are deprived of oxygen for more than four hours arebelieved to lose vigor and not be useful in the recipient because ofischemic/reperfusion injury. See U.S. Pat. No. 6,054,261.

Moreover, many, if not all, of the solutions and containers for organpreservation and transplantation involve hypothermia (temperature belowroom temperature, often near but not below 0° C.), which has been calledthe “bed rock of all useful methods of organ and tissue preservation.”U.S. Pat. No. 6,492,103.

To improve the prospect of a successful transplant, techniques forbetter preserving an organ for transplantation have been developed. Twogeneral areas of development have occurred, one in the area ofpreservation solutions and the other in the area of organ containers.

Moreover, many, if not all, of the solutions and containers for organpreservation and transplantation involve hypothermia (temperature belowroom temperature, often near but not below 0° C.), which has been calledthe “bed rock of all useful methods of organ and tissue preservation.”U.S. Pat. No. 6,492,103.

In the field of organ transplantation, certain conditions are believedto be related to the condition of the organ and prognosis for asuccessful transplantation: 1) minimization of cell swelling and edema;2) prevention of intracellular acidosis; 3) minimization of ischemicdamage; and 4) provision of substrate for regeneration of high energyphosphate compounds and ATP during reperfusion. Ischemic/reperfusioninjury in organ transplantation is especially problematic because theharvested organ is removed from the body, isolated from a blood source,and thereby deprived of oxygen and nutrients for an extended period oftime (U.S. Pat. No. 5,912,019). In fact, one of the most criticalproblems in transplantation today is the relatively high incidence ofdelayed graft function (DGF) due to acute tubular necrosis (ATN) aftersurgery. Current methods still experience problems in these areas, whichhighlights the importance of the present invention.

Nonetheless, the present invention can be used in conjunction with otherpreservation compositions and methods. As discussed in U.S. Pat. Nos.5,952,168, 5,217,860, 4,559,258 and 6,187,529 (incorporated specificallyby reference), biological materials can be preserved, for example, forkeeping transplantable or replaceable organs long-term.

Cells, tissue/organs, or cadavers can be given compounds that enhance ormaintain the condition of organs for transplantation. Such methods andcompositions include those described in U.S. Pat. Nos. 5,752,929 and5,395,314.

Moreover, methods of the present invention can include exposingbiological matter to preservation solutions, such as those discussed, inaddition to exposure to an oxygen antagonist or other active compound.

It is contemplated that any agent or solution used with a biologicalsample that is living and that will be used as a living material will bepharmaceutically acceptable or pharmacologically acceptable. The phrase“pharmaceutically-acceptable” or “pharmacologically-acceptable” refersto molecular entities and compositions that do not produce an allergicor similar untoward reaction when administered to a human. Thepreparation of an aqueous composition that contains a protein as anactive ingredient is well understood in the art. Typically, suchcompositions are prepared either as liquid solutions or suspensions;solid forms suitable for solution in, or suspension in, liquid prior touse can also be prepared.

Organs for transplants may be monitored to assess their condition,particularly with respect to use as a transplant. Such methods aredescribed in U.S. Pat. No. 5,699,793.

A number of drugs can be administered to a patient after receiving anorgan transplant to assist in the recovery process. Such drugs includecompounds and agents that reduce or inhibit an immune response againstthe donated organ.

Moreover, additional drugs are continually being researched and offeredfor use in organ transplants, such as those described in U.S. Pat. No.6,552,083 (inhibitory agent comprisingN-(3,4-dimethoxycinnamoyl)anthranililc acid) and 6,013,256 (antibodiesthat bind the IL-2 receptor, such as a humanized anti-Tax antibody).

H. Preservation Apparatuses and Applications

Systems or containers for transporting organs and tissues have also beendeveloped through the years. Any of these embodiments may be combinedwith apparatuses of the invention, which allow for use with oxygenantagonists or other active compound.

Most involve cooling systems for implementation, for example, thosedescribed in U.S. Pat. Nos. 4,292,817, 4,473,637, and 4,745,759, whichemploy active refrigeration with a cooling liquid that is pumped throughthe system. Several sophisticated devices have been designed involvingmultiple chambers or dual containers, such as is U.S. Pat. Nos.5,434,045 and 4,723,974.

Some constitute a system in which an apparatus is devised for perfusionof the organ or tissue in a preservation solution, as is described inU.S. Pat. Nos. 6,490,880; 6,100,082; 6,046,046; 5,326,706; 5,285,657;5,157,930; 4,951,482; 4,502,295; and, 4,186,565.

Some of the systems and solutions for organ preservation specificallyinvolve oxygen perfusion in the solution or system to expose the organto oxygen because it is believed that maintaining the organ or tissue inan oxygenated environment improves viability. See Kuroda et al.,(Transplantation 46(3):457-460, 1988) and U.S. Pat. Nos. 6,490,880;6,046,046; 5,476,763; 5,285,657; 3,995,444; 3,881,990; and, 3,777,507.Isolated hearts that are deprived of oxygen for more than four hours arebelieved to lose vigor and not be useful in the recipient because ofischemic/reperfusion injury. See U.S. Pat. No. 6,054,261.

Moreover, in some embodiments of the invention, there are methods forpreserving platelets, as mentioned above. Shortcomings of the prior artare reduced or eliminated using techniques of this disclosure.Embodiments concerning platelets and oxygen reduction find wideapplication including but not limited to any application that wouldbenefit from longer-lasting storage of platelets.

In one embodiment, oxygen reduction techniques can be embodied in a kit.For example, the kit currently sold under product number 261215,available from Becton Dickinson, makes use of select techniquesdescribed here. That kit includes an anaerobic generator (e.g., ahydrogen gas generator), Palladium Catalysts, an anaerobic indicator,and a gas impermeable, sealable, “BioBag” into which the abovecomponents (together with platelets in a gas-perneable bag) are placedand sealed.

The anaerobic generator of this example kit is activated by the additionof water, which passes through a series of channels to a filter paperwick. The wick delays and regulates the introduction of water into thetablet chamber, providing a controlled release of hydrogen gas. Thegas-generating tablet includes sodium borohydride. The hydrogen releasedfrom this reaction combines with the atmospheric oxygen in the sealedcontainer to produce water. This reaction is catalyzed by the palladiumin the container.

In a more general respect, techniques of this disclosure can be carriedout using any number of sealed environments (e.g., a container such as ajar, impermeable bag, or chamber) in which oxygen tension can bereduced. In one embodiment, an oxygen level within the container and/orwithin platelets or an associated solution may be reduced to less thanabout 1% (about 10,000 parts per million). In another embodiment, theoxygen may be reduced to about a range of 10-100 parts per million, orless. In still other embodiments, the oxygen may be reduced to anypercentage value that represents a decrease in oxygen within a containerand/or within platelets or an associated solution. In preferredembodiments, the container is gas-impermeable, as well as sealable. Asthose having ordinary skill in the art will appreciate “gas impermeable”does not necessarily connote an absolute or 100% level ofimpermeability. Rather, “gas impermeable” should be interpreted as it isin the art to signify, e.g., able to hold an atmosphere that is lessthan 10 ppm (against a gradient of room air, typically 210,000 ppm) forat least 4 days. Typically, commercially available bags are impermeablefor 6 weeks or longer.

A container may be sealed once pertinent oxygen reducing elements areplaced inside. The reduction in atmospheric oxygen in this environmentmay be achieved by the generation of hydrogen gas, with or without acatalyst, to combine with the oxygen to produce water. Other reactionsmay be catalyzed to combine the oxygen with other compounds, such ascarbon to produce carbon dioxide. Other reactions and combinations willbe apparent to those having ordinary skill in the art. Also, oxygen maybe replaced by exchanging gases in the chamber with gas containing anycombination of gases that do not include oxygen. Additionally, oxygenmay be removed by placing a container under a vacuum sufficient toremove gases and particularly sufficient to remove oxygen to a desired,reduced level. Alternatively, oxygen may be competed by using anothergas or compound that competes for oxygen, such as CO. A combination ofremoval of oxygen and competition of remaining oxygen may be used.

In different embodiments, a device may be used to measure oxygen levelsto ensure the appropriate anaerobic state has been achieved. Ananaerobic indicator based on methlyene blue that changes from blue colorto colorless in the absence of oxygen may be used. Alternatively, acommercially available oxygen meter (e.g., a mechanical and/orelectrical meter) or other oxygen measuring device may be used.

In different embodiments, platelets are contained in a sealedenvironment such that oxygen can be removed from the solution containingthe platelets, as well as from the platelets themselves. For example,platelets in a gas-permeable bag may be placed inside a sealedenvironment. Other non-limiting examples may be to have an opencontainer inside a sealed environment to hold platelets. Alternatively,one may contain platelets in an impermeable, sealed container (e.g., abag) and have an oxygen removal mechanism incorporated.

In one embodiment, the invention involves a method in which plateletsand a solution are introduced into a gas-impermeable container. Thecontainer is sealed. Oxygen is removed from the container or from theplatelets and solution. It is contemplated that about, at least about,or at most about 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87,88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100%, or any rangederivable therein, of the oxygen in the gas permeable bag is removed.

This method may also include indicating a remaining oxygen level withinthe container following oxygen removal. Oxygen in the container may bereduced to a level of about 10,000 parts per million or less. Oxygen inthe container may be reduced to a level between about 10 and about 100parts per million. Introducing the platelets may involve inserting agas-permeable container holding the platelets and solution into thegas-impermeable container. Introducing the platelets may involveinserting the platelets and solution into a sealable, flexible bag or asealable, rigid chamber. Sealing the container, which can occur at anystage of a given process, can involve the use of an adhesive.

Removing oxygen may involve pumping oxygen from the container, and suchpumping may involve pumping with a roughing and/or turbo pump. Removingoxygen may involve introducing hydrogen into the container, whichcombines with the oxygen to produce water. The hydrogen may beintroduced through a chemical reaction. The chemical reaction may becatalyzed. Removing oxygen may involve introducing hydrogen into thecontainer using a gas generating tablet. Water may be added to a gasgenerating tablet comprising sodium borohydride to generate hydrogen.Such water may be added in a delayed and regulated manner. For example,a filter paper wick may be used. Water may be introduced to the filterpaper wick through one or more channels. Palladium may catalyze achemical reaction that generates hydrogen. Removing oxygen may involveintroducing one or more agents into the container that bond with theoxygen. CO may be introduced into the container, which bonds with theoxygen to form CO₂. Removing oxygen may involve displacing oxygen withone or more gases.

Indicating a remaining oxygen level may involve use of a methlyene blueindicator that changes color in the absence of oxygen. Alternatively, anoxygen meter may be used. Indicating a remaining oxygen level within thecontainer may involve indicating a remaining oxygen level withinplatelets or a solution.

In one embodiment, the invention involves a method in which plateletsand a solution are introduced into a gas-impermeable container. Thecontainer is sealed. Hydrogen is generated through a chemical reactionby adding water to sodium borohydride. The chemical reaction removesoxygen from the platelets and solution through combination with thehydrogen to form water. A remaining oxygen level is indicated within thecontainer following oxygen removal.

The chemical reaction may be catalyzed using palladium. The addition ofwater may involve use of a filter paper wick.

In one embodiment, the invention involves a system for removing oxygenfrom platelets and a solution. The system includes (a) a sealable,gas-impermeable container, (b) an oxygen-reducing generator, and (c) anoxygen indicator. The sealable, gas-impermeable container is configuredand sized to receive the platelets and the solution. The oxygen-reducinggenerator is coupled to the container and is configured to remove oxygenfrom the platelets and the solution through pumping or chemicalreaction. The oxygen indicator is coupled to the container and isconfigured to indicate an oxygen level within the container followingoxygen removal.

The container may be a sealable, flexible bag. The oxygen reducinggenerator may include a hydrogen generator configured to generatehydrogen for combining with the oxygen to produce water. The hydrogengenerator may include a gas generating substance that, when combinedwith an agent, generates the hydrogen. That gas generating substance mayinclude a sodium borohydride tablet, and the agent may include water. Ahydrogen generator may also include a palladium catalyst. The system mayalso include a member configured to delay or regulate a chemicalreaction by controlling the introduction of one or more components ofthe chemical reaction. For example, the member can include a wick thatdelays and regulates a chemical reaction.

In one embodiment, the invention involves a kit including a hydrogengenerator; a gas impermeable, sealable container; and an oxygenindicator.

The hydrogen generator may include a gas generating substance that, whencombined with an agent, generates the hydrogen. That gas generatingsubstance may include a sodium borohydride tablet, and the agent mayinclude water. The kit may also include a palladium catalyst. The kitmay also include a wick configured to delay or regulate a chemicalreaction that generates the hydrogen.

As discussed above, methods of the invention can involve employing anapparatus or system that maintains the environment in which biologicalmatter is placed or exposed to. The invention includes an apparatus inwhich an active compound, particularly as a gas, is supplied. In someembodiments, the apparatus includes a container with a sample chamberfor holding the biological matter, wherein the container is connected toa supply of gas comprising the active compound(s). It is specificallycontemplated that the container may be a solid container or it mayflexible, such as a bag.

In some embodiments, the invention is an apparatus for preservingcell(s), the apparatus comprising: a container having a sample chamberwith a volume of no greater than 775 liters; and a first gas supply influid communication with the sample chamber, the first gas supplyincluding carbon monoxide. In further embodiments, the apparatus alsoincludes a cooling unit that regulates the temperature inside the samplechamber and/or a gas regulator that regulates the amount of activecompound in the chamber or the amount of active compound in a solutionthat is in the chamber.

It is contemplated that there may be a gas supply for a second oradditional gas or a second or additional gas supply for the activecompound. The second gas supply may be connected with the sample chamberor it may be connected with the first gas supply. The additional gas, asdiscussed above, may be a non-toxic and/or non-reactive gas.

A gas regulator is part of the apparatus in some embodiments of theinvention. One, two, three, or more gas regulators may be employed. Insome cases, the gas regulator regulates the gas supplied to the samplechamber from the first gas supply. Alternatively, it regulates the gassupplied to the sample chamber or first gas supply from the second gassupply, or there may be a regulator for both the first and second gassupplies. It is further contemplated that any gas regulator can beprogrammed to control the amount of gas supplied to the sample chamberand/or to another gas supply. The regulation may or may not be for aspecified period of time. There may be a gas regulator, which may or maynot be programmable, for any gas supply directly or indirectly connectedto the sample chamber. In some cases, the gas regulator iselectronically programmable.

In some cases, the pressure and/or the temperature inside the chambercan be regulated with either a pressure regulator or temperatureregulator, respectively. As with the gas regulator, these regulators maybe electronically programmable. The apparatus of the invention may alsohave a cooling and/or heating unit to achieve the temperatures discussedabove. The unit may or may not be electronically programmable.

In additional embodiments, the apparatus includes a wheeled cart onwhich the container rests or it may have one or more handles.

It is specifically contemplated that the invention includes an apparatusfor cell(s), in which the apparatus has: a container having a samplechamber; a first gas supply in fluid communication with the samplechamber, the first gas supply including the active compound(s); and anelectronically-programmable gas regulator that regulates gas supplied tothe sample chamber from the first gas supply.

In some embodiments, the apparatus also has a structure configured toprovide a vacuum within the sample chamber.

Moreover, any oxygen antagonist described in this application iscontemplated for use with apparatuses of the invention. In specificembodiments, carbon monoxide can be administered using this apparatus.In other cases, a chalcogenide compound can be administered or acompound having the reducing agent structure.

FIG. 19 is a schematic diagram of an example system for removing oxygenfrom platelets and a solution and embodies concepts discussed above. Gaspermeable bag 1902 may be placed in sealable gas impermeable container1904. Gas impermeable container 1904 may be coupled to oxygen reducinggenerator 1906. Oxygen reducing generator 1906, in one embodiment, mayenvelope sealable gas impermeable container 1904. In differentembodiments, oxygen reducing generator 1906 may take different forms.For example, it may be a pump (e.g., a roughing or and/or turbo pump) ora hydrogen generator. Associated with oxygen reducing generator 1906 maybe one or more components such as a wick or other delay mechanism.Coupled to sealable gas impermeable container 1904 are sensor 1908 andregulator 1910. Sensor 1908, in one embodiment, may be an oxygen meter,which may take various forms. In other embodiments, sensor 1908 may be atemperature or pressure meter. Of course, more than one sensor may beused. In one embodiment, regulator 1901 may be a temperature or pressureregulator. For example, regulator 1901 may be a heater or cooling deviceto regulate temperature inside sealable gas impermeable container 1904.

V. Diagnostic Applications

Sulfites are produced by all cells in the body during normal metabolismof sulfur containing amino acids. Sulfite oxidase, removes, and thusregulates the levels of sulfites. Differential activities of theseenzymes would lead to different levels of sulfites evolved in tissuespecific manner. In the example described above, for solid tumors inhypoxic conditions, sulfites may be produced at higher levels to providelocal protective state to the tumor cells through the reduction ofmetabolic state as well as the inhibition of immune surveillance.Therefore, it would be beneficial to measure sulfite levels andincorporate this as part of diagnosis for several disease states such assolid tumors. Furthermore, since we propose using sulfites for variousapplications, it would be useful to follow this using some sort ofimaging or other monitoring process.

It is possible to measure sulfite levels in serum to get a total sulfitelevel using current technology (e.g., HPLC). It is worth exploring thepossibility of imaging sulfites. Alternatively, a proteomic approach mayallow an understanding of how the regulation of the enzymes involved insulfite metabolism may be altered in certain disease states, allowingfor this approach to diagnostics.

VI. Screening Applications

In still further embodiments, the present invention provides methods foridentifying oxygen antagonists and molecules that act in a like fashionwith respect to inducing stasis and other active compounds. In somecases, the oxygen antagonist or active compounds being sought works likea chalcogenide compound in reducing core body temperature or preservingviability in hypoxic or anoxic environments that would otherwise killthe biological matter if it were not for the presence of the oxygenantagonist or other active compound. These assays may comprise randomscreening of large libraries of candidate substances; alternatively, theassays may be used to focus on particular classes of compounds selectedwith an eye towards attributes that are believed to make them morelikely to act as oxygen antagonists or active compounds. providing acandidate active compound;

-   -   (a) admixing the candidate active compound with a biological        matter;    -   (b) measuring one or more cellular responses characteristic of        oxygen antagonist treatment; and    -   (c) comparing the one or more responses with the biological        matter in the absence of the candidate active compound.        Assays may be conducted with isolated cells, tissues/organs, or        intact organisms.

It will, of course, be understood that all the screening methods of thepresent invention are useful in themselves notwithstanding the fact thateffective candidates may not be found. The invention provides methodsfor screening for such candidates, not solely methods of finding them.However, it will also be understand that cadidate active compound may beidentified as an effective active compound according to one or moreassays, meaning that the candidate active compound appears to have someability to act as an active compound, such as by inducing stasis in abiological matter. Screening, in some embodiments, involves using anassay described in the Examples or elsewhere in the disclosure toidentify a modulator. Moreover, in addition to or instead of the methoddescribed in this section, a candidate active compound may be tested foractivity either as an oxygen antagonist or as another compound having aproperty of an active compound, such as protective metabolic agent ortherapeutic substance. Some embodiments of screening methods areprovided above.

An effective active compound may be further characterized or assayed.Moreover, the effective active compound may be used in an in vivo animalor animal model (as discussed below) or be used in further in vivoanimals or animal models, which may involve the same species of animalsor in different animal species.

Furthermore, it is contemplated that an active compound identifiedaccording to embodiments of the invention may also be manufactured afterscreening. Also, biological matter may be exposed to or contacted withan effective active compound according to methods of the invention,particularly with respect to therapeutic or preservation embodiments.

A. Active Compounds

As used herein the term “candidate active compound” refers to anymolecule that may induce stasis in biological matter by, for example,altering core body temperature. The candidate active compound may be aprotein or fragment thereof, a small molecule, or even a nucleic acidmolecule. One may also acquire, from various commercial sources, smallmolecule libraries that are believed to meet the basic criteria foruseful drugs in an effort to “brute force” the identification of usefulcompounds. Screening of such libraries, including combinatoriallygenerated libraries (e.g., peptide libraries), is a rapid and efficientway to screen large number of related (and unrelated) compounds foractivity. Combinatorial approaches also lend themselves to rapidevolution of potential drugs by the creation of second, third and fourthgeneration compounds modeled of active, but otherwise undesirablecompounds.

Candidate active compounds may include fragments or parts ofnaturally-occurring compounds, or may be found as active combinations ofknown compounds, which are otherwise inactive. It is proposed thatcompounds isolated from natural sources, such as animals, bacteria,fungi, plant sources, including leaves and bark, and marine samples maybe assayed as candidates for the presence of potentially usefulpharmaceutical agents. It will be understood that the pharmaceuticalagents to be screened could also be derived or synthesized from chemicalcompositions or man-made compounds. Thus, it is understood that thecandidate active compound identified by the present invention may bepeptide, polypeptide, polynucleotide, small molecule inhibitors or anyother compounds that may be designed through rational drug designstarting from known inhibitors or stimulators.

Other suitable active compounds include antisense molecules, siRNAs,ribozymes, and antibodies (including single chain antibodies), each ofwhich would be specific for the target molecule. Such compounds aredescribed in greater detail elsewhere in this document. For example, anantisense molecule that bound to a translational or transcriptionalstart site, or splice junctions, would be ideal candidate inhibitors.

In addition to the active compounds initially identified, the inventoralso contemplates that other structurally similar compounds may beformulated to mimic the key portions of the structure of the activecompounds. Such compounds, which may include peptidomimetics of peptidemodulators, may be used in the same manner as the initial activecompounds.

B. In vivo Assays

In vivo assays involve the use of various animal models. Due to theirsize, ease of handling, and information on their physiology and geneticmake-up, mice are a preferred embodiment. However, other animals aresuitable as well, including rats, rabbits, hamsters, guinea pigs,gerbils, woodchucks, mice, cats, dogs, sheep, goats, pigs, cows, horsesand monkeys (including chimps, gibbons and baboons). Fish are alsocontemplated for use with in vivo assays, as are nematodes. Assays formodulators may be conducted using an animal model derived from any ofthese species.

In such assays, one or more candidate substances are administered to ananimal, and the ability of the candidate substance(s) to induce stasis,reduce core body temperature, or endow on the biological material theability to survive hypoxic or anoxic environmental conditions, ascompared to an inert vehicle (negative control) and H₂S (positivecontrol), identifies a modulator. Treatment of animals with testcompounds will involve the administration of the compound, in anappropriate form, to the animal. Administration of the candidatecompound (gas or liquid) will be by any route that could be utilized forclinical or non-clinical purposes, including but not limited to oral,nasal (inhalation or aerosol), buccal, or even topical. Alternatively,administration may be by intratracheal instillation, bronchialinstillation, intradermal, subcutaneous, intramuscular, intraperitonealor intravenous injection. Specifically contemplated routes are systemicintravenous injection, regional administration via blood or lymphsupply, or directly to an affected site.

VII. Modes of Administration and Pharmaceutical Compositions

An effective amount of a pharmaceutical composition of a chalcogenide,oxygen antagonist, or their active compound, generally, is defined asthat amount sufficient to detectably ameliorate, reduce, minimize orlimit the extent of the condition of interest. More rigorous definitionsmay apply, including elimination, eradication or cure of disease.

A. Administration

The routes of administration of a chalcogenide or other active compoundwill vary, naturally, with the location and nature of the condition tobe treated, and include, e.g., inhalation, intradermal, transdermal,parenteral, intravenous, intramuscular, intranasal, subcutaneous,percutaneous, intratracheal, intraperitoneal, intratumoral, perfusion,lavage, direct injection, and oral administration and formulation. Asdetailed below, active compounds may be administered as medical gases byinhalation or intubation, as injectable liquids by intravascular,intravenous, intra-arterial, intracerobroventicular, intraperitoneal,subcutaneous administration, as topical liquids or gels, or in solidoral dosage forms.

Moreover, the amounts may vary depending on the type of biologicalmatter (cell type, tissue type, organism genus and species, etc.) and/orits size (weight, surface area, etc.). It will generally be the casethat the larger the organism, the larger the dose. Therefore, aneffective amount for a mouse will generally be lower than an effectiveamount for a rat, which will generally be lower than an effective amountfor a dog, which will generally be lower than an effective amount for ahuman. The effective concentration of hydrogen sulfide to achieve stasisin a human depends on the dosage form and route of administration. Forinhalation, in some embodiments effective concentrations are in therange of 50 ppm to 500 ppm, delivered continuously. For intravenousadministration, in some embodiments effective concentrations are in therange of 0.5 to 50 milligrams per kilogram of body weight deliveredcontinuously.

Similarly, the length of time of administration may vary depending onthe type of biological matter (cell type, tissue type, organism genusand species, etc.) and/or its size (weight, surface area, etc.) and willdepend in part upon dosage form and route of administration. Inparticular embodiments, an active compound is provided for about or atleast 30 seconds, 1 minute, 2 minutes, 3 minutes, 5 minutes, 10 minutes,15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, four hours five hours,six hours, eight hours, twelve hours, twenty-four hours, or greater thantwenty-four hours. An active compound may be administered in a singledos or multiple doses, with varying amounts of time between administereddoses.

In the case of transplant, the present invention may be used pre- and orpost-operatively to render host or graft materials quiescent. In aspecific embodiment, a surgical site may be injected or perfused with aformulation comprising a chalcogenide. The perfusion may be continuedpost-surgery, for example, by leaving a catheter implanted at the siteof the surgery.

B. Injectable Compositions and Formulations

The preferred methods for the delivery of oxygen antagonists or otheractive compound of the present invention are inhalation, intravenousinjection, perfusion of a particular area, and oral administration.However, the pharmaceutical compositions disclosed herein mayalternatively be administered parenterally, intradermally,intramuscularly, transdermally or even intraperitoneally as described inU.S. Pat. No. 5,543,158; U.S. Pat. No. 5,641,515 and U.S. Pat. No.5,399,363 (each specifically incorporated herein by reference in itsentirety).

Solutions of the active compounds may be prepared in water suitablymixed with a surfactant, such as hydroxypropylcellulose. Dispersions mayalso be prepared in glycerol, liquid polyethylene glycols, and mixturesthereof and in oils. Under ordinary conditions of storage and use, thesepreparations contain a preservative to prevent the growth ofmicroorganisms. The pharmaceutical forms suitable for injectable useinclude sterile aqueous solutions or dispersions and sterile powders forthe extemporaneous preparation of sterile injectable solutions ordispersions (U.S. Pat. No. 5,466,468, specifically incorporated hereinby reference in its entirety). In all cases the form must be sterile andmust be fluid to the extent that easy syringability exists. It must bestable under the conditions of manufacture and storage and must bepreserved against the contaminating action of microorganisms, such asbacteria and fungi. The carrier can be a solvent or dispersion mediumcontaining, for example, water, ethanol, polyol (e.g., glycerol,propylene glycol, and liquid polyethylene glycol, and the like),suitable mixtures thereof, and/or vegetable oils. Proper fluidity may bemaintained, for example, by the use of a coating, such as lecithin, bythe maintenance of the required particle size in the case of dispersionand by the use of surfactants. The prevention of the action ofmicroorganisms can be brought about by various antibacterial andantifungal agents, for example, parabens, chlorobutanol, phenol, sorbicacid, thimerosal, and the like. In many cases, it will be preferable toinclude isotonic agents, for example, sugars or sodium chloride.Prolonged absorption of the injectable compositions can be brought aboutby the use in the compositions of agents delaying absorption, forexample, aluminum monostearate and gelatin.

For parenteral administration in an aqueous solution, for example, thesolution should be suitably buffered if necessary and the liquid diluentfirst rendered isotonic with sufficient saline or glucose. Theseparticular aqueous solutions are especially suitable for intravenous,intramuscular, subcutaneous, intratumoral and intraperitonealadministration. In this connection, sterile aqueous media that can beemployed will be known to those of skill in the art in light of thepresent disclosure. For example, one dosage may be dissolved in 1 ml ofisotonic NaCl solution and either added to 1000 ml of hypodermoclysisfluid or injected at the proposed site of infusion, (see for example,“Remington's Pharmaceutical Sciences” 15th Edition, pages 1035-1038 and1570-1580). Some variation in dosage will necessarily occur depending onthe condition of the subject being treated. The person responsible foradministration will, in any event, determine the appropriate dose forthe individual subject. Moreover, for human administration, preparationsshould meet sterility, pyrogenicity, general safety and purity standardsas required by FDA Office of Biologics standards.

Sterile injectable solutions are prepared by incorporating the activecompounds in the required amount in the appropriate solvent with variousother ingredients enumerated above, as required, followed by filteredsterilization. Generally, dispersions are prepared by incorporating thevarious sterilized active ingredients into a sterile vehicle whichcontains the basic dispersion medium and the required other ingredientsfrom those enumerated above. In the case of sterile powders for thepreparation of sterile injectable solutions, the preferred methods ofpreparation are vacuum-drying and freeze-drying techniques which yield apowder of the active ingredient plus any additional desired ingredientfrom a previously sterile-filtered solution thereof.

As used herein, “carrier” includes any and all solvents, dispersionmedia, vehicles, coatings, diluents, antibacterial and antifungalagents, isotonic and absorption delaying agents, buffers, carriersolutions, suspensions, colloids, and the like. The use of such mediaand agents for pharmaceutical active substances is well known in theart. Except insofar as any conventional media or agent is incompatiblewith the active ingredient, its use in the therapeutic compositions iscontemplated. Supplementary active ingredients can also be incorporatedinto the compositions.

The phrase “pharmaceutically-acceptable” or“pharmacologically-acceptable” refers to molecular entities andcompositions that do not produce an allergic or similar untowardreaction when administered to a human. The preparation of an aqueouscomposition that contains a protein as an active ingredient is wellunderstood in the art. Typically, such compositions are prepared asinjectables, either as liquid solutions or suspensions; solid formssuitable for solution in, or suspension in, liquid prior to injectioncan also be prepared.

C. Intravenous Formulations

In one embodiment, active compounds of the invention may be formulatedfor parenteral administration (e.g., intravenous, intra-arterial). Inthe cases where the active compound is a gas at room temperature, asolution containing a known and desired concentration of the gasmolecule dissolved in a liquid or a solution for parenteraladministration is contemplated. Preparation of the active compoundsolution may be achieved by, for example, contacting (e.g., bubbling orinfusing) the gas with the solution to cause the gas molecules todissolve in the solution. Those skilled in the art will recognize thatthe amount of gas that dissolves in the solution will depend on a numberof variables including, but not limited to, the solubility of the gas inthe liquid or solution, the chemical composition of the liquid orsolution, its temperature, its pH, its ionic strength, as well as theconcentration of the gas and the extent of contacting (e.g., rate of andduration of bubbling or infusing). The concentration of the activecompound in the liquid or solution for parenteral administration can bedetermined using methods known to those skilled in the art. Thestability of the active compound in the liquid or solution can bedetermined by measuring the concentration of the dissolved oxygenantagonist after varying intervals of time following preparation ormanufacture of the oxygen antagonist solution, where a decrease in theconcentration of the oxygen antagonist compared to the startingconcentration is indicative of loss or chemical conversion of the activecompound.

In some embodiments, there is a solution containing a chalcogenidecompound is produced by dissolving a salt form of the chalcogenide intosterile water or saline (0.9% sodium chloride) to yield apharmaceutically acceptable intravenous dosage form. The intravenousliquid dosage form may be buffered to a certain pH to enhance thesolubility of the chalcogenide compound or to influence the ionizationstate of the chalcogenide compound. In the cases of hydrogen sulfide orhydrogen selenide, any of a number of salt forms known to those skilledin the art may suffice, including, but not limited to, sodium, calcium,barium, lithium, or potassium. In another preferred embodiment, sodiumsulfide or sodium selenide is dissolved in sterile phosphate bufferedsaline and the pH is adjusted to 7.0 with hydrochloric acid to yield asolution of known concentration which can be administered to a subjectintravenously or intrarterially.

It is contemplated that in some embodiments, a pharmaceuticalcomposition of the invention is a saturated solution with respect to theactive compound. The solution can be any pharmaceutically acceptableformulation, many of which are well known, such as Ringer's solution. Incertain embodiments, the concentration of the active compound is about,at least about, or at most about 0.001, 0.01, 0.02, 0.03, 0.04, 0.05,0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3,2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6,3.7.3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0 M ormore, or any range derivable therein (at standard temperature andpressure (STP)). With H₂S, for example, in some embodiments, theconcentration can be from about 0.01 to about 0.5 M (at STP). It isspecifically contemplated the above concentrations may be applied withrespect to carbon monoxide and carbon dioxide in a solution separatelyor together.

Furthermore, when administration is intravenous, it is contemplated thatthe following parameters may be applied. A flow rate of about, at leastabout, or at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 gtts/min orμgtts/min, or any range derivable therein. In some embodiments, theamount of the solution is specified by volume, depending on theconcentration of the solution. An amount of time may be about, at leastabout, or at most about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 58, 59, 60 minutes, 1, 2, 3, 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 hours, 1,2, 3, 4, 5, 6, 7 days, 1, 2, 3, 4, 5 weeks, and/or 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12 months, or any range derivable therein.

Volumes of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 110, 120, 130, 140, 150,160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290,300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430,440, 441, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560,570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700,710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840,850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980,990, 1000 mls or liters, or any range therein, may be administeredoverall or in a single session.

In some embodiments, the solution of the active compound for parenteraladministration is prepared in a liquid or solution in which the oxygenhas been removed prior to contacting the liquid or solution with theactive compound. Certain oxygen antagonists, in particular certainchalcogenide compounds (e.g., hydrogen sulfide, hydrogen selenide), arenot stable in the presence of oxygen due to their ability to reactchemically with oxygen, leading to their oxidation and chemicaltransformation. Oxygen can be removed from liquids or solutions usingmethods known in the art, including, but not limited to, application ofnegative pressure (vacuum degasing) to the liquid or solution, orcontacting the solution or liquid with a reagent which causes oxygen tobe bound or “chelated”, effectively removing it from solution.

In another embodiment, the solution of the oxygen antagonist or otheractive compound for parenteral administration may be stored in agas-tight container. This is particularly desirable when the oxygen haspreviously been removed from the solution to limit or prevent oxidationof the oxygen antagonist or other active compound. Additionally, storagein a gas-tight container will inhibit the volatilization of the oxygenantagonist gas or other active compound from the liquid or solution,allowing a constant concentration of the dissolved oxygen antagonist tobe maintained. Gas-tight containers are known to those skilled in theart and include, but are not limited to, “i.v. bags” comprising a gasimpermeable construction material, or a sealed glass vial. To preventexposure to air in the gas-tight storage container, an inert gas, suchas nitrogen or argon, may be introduced into the container prior toclosure.

D. Topical Formulations and Uses Thereof

Methods and compositions of the present invention are useful forinducing stasis in superficial layers of the skin and oral mucosa,including, but not limited to, hair follicle cells, capillaryendothelial cells, and epithelial cells of the mouth and tongue.Radiation therapy and chemotherapy for the treatment of cancer damagenormal cells in the hair follicles and oral mucosa, leading to theunintended, but debilitating side effects of cancer therapy, hair lossand oral mucositis, respectively. Induction of stasis in hair folliclecells and/or the vascular cells that supply blood to the hair folliclesmay slow, limit or prevent damage to hair follicle cells and theresultant hair loss that accompanies radiation therapy and chemotherapy,or other alopecia, male-pattern baldness, female-pattern baldness, orother absence of the hair from skin areas where it normally is present.Induction of stasis in oral epithelial and mesenchymal cells may slow,limit or prevent damage to cells lining the mouth, esophagus and tongueand the resultant painful condition of oral mucositis.

In certain embodiments the active compound is administered topically.This is achieved by formulating the active compound in a cream, gel,paste, or mouthwash and applying such formulation directly to the areasthat require exposure to the active compound (e.g., scalp, mouth,tongue, throat).

The topical compositions of this invention can be formulated as oils,creams, lotions, ointments and the like by choice of appropriatecarriers. Suitable carriers include vegetable or mineral oils, whitepetrolatum (white soft paraffin), branched chain fats or oils, animalfats and high molecular weight alcohol (greater than C₁₂). The preferredcarriers are those in which the active ingredient is soluble.Emulsifiers, stabilizers, humectants and antioxidants may also beincluded as well as agents imparting color or fragrance, if desired.Additionally, transdermal penetration enhancers can be employed in thesetopical formulations. Examples of such enhancers can be found in U.S.Pat. Nos. 3,989,816 and 4,444,762.

Creams are preferably formulated from a mixture of mineral oil,self-emulsifying beeswax and water in which mixture the activeingredient, dissolved in a small amount of an oil such as almond oil, isadmixed. A typical example of such a cream is one which includes about40 parts water, about 20 parts beeswax, about 40 parts mineral oil andabout 1 part almond oil.

Ointments may be formulated by mixing a solution of the activeingredient in a vegetable oil such as almond oil with warm soft paraffinand allowing the mixture to cool. A typical example of such an ointmentis one which includes about 30% almond oil and about 70% white softparaffin by weight.

Lotions may be conveniently prepared by dissolving the activeingredient, in a suitable high molecular weight alcohol such aspropylene glycol or polyethylene glycol.

Possible pharmaceutical preparations that can be used rectally include,for example, suppositories, which consist of a combination of one ormore of the active compounds with a suppository base. Suitablesuppository bases are, for example, natural or synthetic triglycerides,or paraffin hydrocarbons. In addition, it is also possible to usegelatin rectal capsules which consist of a combination of the activecompounds with a base. Possible base materials include, for example,liquid triglycerides, polyethylene glycols, or paraffin hydrocarbons.

E. Solid Dosage Forms

Pharmaceutical compositions include solid dosage forms in which theactive compound is trapped, or sequestered, in a porous carrierframework that is capable of achieving a crystalline, solid state. Suchsolid dosage forms with the capacity for gas storage are known in theart and can be produced in pharmaceutically acceptable forms (e.g.,Yaghi et al. 2003). A particular advantage of such a pharmaceuticalcomposition pertains to chalcogenide compounds (e.g., hydrogen sulfide,carbon monoxide, hydrogen selenide), which can be toxic to certainmammals at certain concentrations in their free form. In certainembodiments, the compound may be formulated for oral administration.

F. Perfusion Systems

A perfusion system for cells may be used to expose a tissue or organ toan active compound in the form of a liquid or a semi-solid. Perfusionrefers to continuous flow of a solution through or over a population ofcells. It implies the retention of the cells within the culture unit asopposed to continuous-flow culture, which washes the cells out with thewithdrawn media (e.g., chemostat). Perfusion allows for better controlof the culture environment (pH, pO₂, nutrient levels, active compoundlevels, etc.) and is a means of significantly increasing the utilizationof the surface area within a culture for cell attachment.

The technique of perfusion was developed to mimic the cells milieu invivo where cells are continuously supplied with blood, lymph, or otherbody fluids. Without perfusion of a physiological nutrient solution,cells in culture go through alternating phases of being fed and starved,thus limiting full expression of their growth and metabolic potential.In the context of the present invention, a perfusion system may also beused to perfuse cells with an oxygen antagonist to induce stasis.

Those of skill in the art are familiar with perfusion systems, and thereare a number of perfusion systems available commercially. Any of theseperfusion systems may be employed in the present invention. One exampleof a perfusion system is a perfused packed-bed reactor using a bedmatrix of a non-woven fabric (CelliGen T, New Brunswick Scientific,Edison, N.J.; Wang et al., 1992; Wang et al., 1993; Wang et al., 1994).Briefly described, this reactor comprises an improved reactor forculturing of both anchorage- and non-anchorage-dependent cells. Thereactor is designed as a packed bed with a means to provide internalrecirculation. Preferably, a fiber matrix carrier is placed in a basketwithin the reactor vessel. A top and bottom portion of the basket hasholes, allowing the medium to flow through the basket. A speciallydesigned impeller provides recirculation of the medium through the spaceoccupied by the fiber matrix for assuring a uniform supply of nutrientand the removal of wastes. This simultaneously assures that a negligibleamount of the total cell mass is suspended in the medium. Thecombination of the basket and the recirculation also provides abubble-free flow of oxygenated medium through the fiber matrix. Thefiber matrix is a non-woven fabric having a “pore” diameter of from 10μm to 100 μm, providing for a high internal volume with pore volumescorresponding to 1 to 20 times the volumes of individual cells.

The perfused packed-bed reactor offers several advantages. With a fibermatrix carrier, the cells are protected against mechanical stress fromagitation and foaming. The free medium flow through the basket providesthe cells with optimum regulated levels of oxygen, pH, and nutrients.Products can be continuously removed from the culture and the harvestedproducts are free of cells and can be produced in low-protein medium,which facilitates subsequent purification steps. This technology isexplained in detail in WO 94/17178 (Aug. 4, 1994, Freedman et al.),which is hereby incorporated by reference in its entirety.

The Cellcube™ (Corning-Costar) module provides a large styrenic surfacearea for the immobilization and growth of substrate attached cells. Itis an integrally encapsulated sterile single-use device that has aseries of parallel culture plates joined to create thin sealed laminarflow spaces between adjacent plates.

The Cellcube™ module has inlet and outlet ports that are diagonallyopposite each other and help regulate the flow of media. During thefirst few days of growth the culture is generally satisfied by the mediacontained within the system after initial seeding. The amount of timebetween the initial seeding and the start of the media perfusion isdependent on the density of cells in the seeding inoculum and the cellgrowth rate. The measurement of nutrient concentration in thecirculating media is a good indicator of the status of the culture. Whenestablishing a procedure it may be necessary to monitor the nutrientscomposition at a variety of different perfusion rates to determine themost economical and productive operating parameters.

Other commercially available perfusion systems include, for example,CellPerf® (Laboratories MABIO International, Tourcoing, France) and theStovall Flow Cell (Stovall Life Science, Inc., Greensboro, N.C.)

The timing and parameters of the production phase of cultures depends onthe type and use of a particular cell line. Many cultures require adifferent media for production than is required for the growth phase ofthe culture. The transition from one phase to the other will likelyrequire multiple washing steps in traditional cultures. However, one ofthe benefits of a perfusion system is the ability to provide a gentletransition between various operating phases. The perfusion system canalso facilitate the transition from a growth phase to a static phaseinduced by an oxygen antagonist. Likewise, the perfusion system canfacilitate the transition from a static phase to a growth phase byreplacing the solution comprising an oxygen antagonist with, forexample, a physiological nutrient media.

G. Catheters

In certain embodiments, a catheter is used to provide an active compoundto an organism. Of particular interest is the administration of such anagent to the heart or vasculature system. Frequently, a catheter is usedfor this purpose. Yaffe et al., 2004 discusses catheters particularly inthe context of suspended animation, though the use of catheters weregenerally known prior to this publication.

H. Delivery of Gases

1. Respiration System

An exemplary gas delivery system 100 is illustrated in FIG. 9. Thedelivery system 100 is suited for delivering breathable gases, includingan active agent, to the respiration system of a subject. The gasdelivery system 100 includes one or more gas sources 102. Each of thegas sources 102 is connected to a regulator 104 and a flowmeter 106. Thegas delivery system 100 also includes an active agent source 107, anoptional vaporizer 108, an outlet controller 110, a scavenger 112, andan alarm/monitoring system 114.

The delivery system 100 may include certain elements generally used inan anesthesia delivery machine. For example, anesthesia deliverymachines generally include a high pressure circuit, a low pressurecircuit, a breathing circuit, and a scavenging circuit. As described inFIGS. 10-11, one or more of the gas sources 102, the vaporizer 108, theoutlet controller 110, the scavenger 112, and/or the alarm/monitoringsystem 114 may be provided as part of a device having a high pressure,low pressure, breathing, and/or scavenging circuit, and these elementsmay be similar to those generally used in an anesthesia deliverymachine. Anesthesia delivery machines are described, for example, inU.S. Pat. Nos. 4,034,753; 4,266,573; 4,442,856; and 5,568,910, thecontents of which are hereby incorporated by reference in theirentireties.

The gas sources 102 may be provided by tanks of compressed gas; however,it should be understood that the gas sources 102 can be either a gas ora liquid source that is converted to a gas. For example, the vaporizer108 can be used to vaporize a liquid gas source. The regulators 104include valves that reduce the pressure of each of the gas sources 102.The decompressed gas then passes through one of the flowmeters 106,which measures and controls the flow of gas from each of the respectivegas sources 102.

The gas sources 102 may be carrier gases that are used to deliver theactive agent 107. The carrier gases may be selected to provide a desiredenvironment for a subject to which the active agent from the source 107is delivered. For example, if the active agent is delivered to a patientas a breathable gas, the carrier gases can include oxygen, nitrousoxide, or air in sufficient quantities to satisfy the needs of thepatient. Other inert or active gases may be used.

In some embodiments, one of the gas sources 102 includes the activeagent source 107. The active agent from the source 107 may be a liquidgas source that is vaporized by the vaporizer 108 or the active agentmay be a gaseous source, such as a compressed gas under high pressure.The active agent can be mixed with one or more of the gas sources 102.The outlet controller 110 controls the amount of the gas mixture that isprovided to the subject.

The scavenger 112 is a device or system that scavenges and/or ventilatesthe gases that are provided to the subject. For example, if the activeagent from the source 107 is provided as a breathable gas to a patient,the scavenger 112 can be used to remove the waste gases of the inhalant(such as the active agent), unused oxygen, and exhaled carbon dioxide.

The alarm/monitoring system 114 includes sensors that monitor the gasflow and/or gas content at one or more locations within the deliverysystem 100. For example, the flow or amount of oxygen may be monitoredwhen the active agent from the source 107 is provided as a breathablegas to a patient to ensure that the carrier gases include sufficientoxygen for the patient. The alarm/monitoring system 114 also includes auser interface that is configured to provide an audio or visual alarm ormonitoring information to a user of the delivery system 100, such as avisual display, a light, or audio alarm. The alarm/monitoring system 114can be configured to notify the user when a predetermined condition ismet and/or to provide information regarding gas levels.

With reference to FIG. 10, a system 100A includes a high pressurecircuit 116, a low pressure circuit 118, a breathing circuit 120, and ascavenging circuit 122.

The high pressure circuit 116 includes the compressed gas sources 102,which are connected to regulator valves 104 b, 104 a. The regulatorvalves 104 a control the amount of gas that flows from each of the gassources 102, and the regulator valves 104 b may be opened to increasethe pressure of the gas, for example, by providing an opening to thesurrounding atmosphere.

The low pressure circuit 118 includes the flowmeters 106, the activeagent source 107, and the vaporizer 108. A gas mixture from the gassources 102 is provided by the flowmeters 106, which control the amountof each of the gases from the gas sources 102. As illustrated in FIG.10, the active agent source 107 is a liquid. The active agent source 107is vaporized by the vaporizer 108 and added to the gas mixture.

The breathing circuit 120 includes the outlet controller 110, twoone-way valves 124, 126 and an absorber 128. The scavenger circuit 122includes a valve 112 a, a reservoir 112 b, and an outlet 112 c. Asubject 130 receives the gas mixture from the outlet controller 110 andthe resulting gas is ventilated by the scavenger circuit 122. Morespecifically, the outlet controller 110 controls the amount of the gasmixture that is delivered to the subject 130 via the one-way valve 124.Expired gases flow through the one-way valve 126 to the valve 112 a andto the reservoir 112 b. Excess gases exit through the outlet 112 c ofthe scavenger 112. Some of the gases may be recycled and flow throughthe absorber 128 and into the breathing circuit 120. The absorber 128may be a carbon dioxide absorbing canister for reducing carbon dioxidegases from exhaled gases. In this configuration, expired oxygen and/oractive agent may be re-circulated and reused.

One or more sensors S may be added at various positions in the system100A. The sensors S sense and/or monitor the gases in the system 100A.For example, if one of the gas sources 102 is oxygen, one of the sensorsS may be an oxygen sensor configured and positioned to monitor theoxygen in the system 100A so that the patient receives a suitable amountof oxygen. The sensors S are in communication with the alarm/monitoringsystem 114 (see FIG. 9). If undesirable or dangerous gas levels arepresent in the system 100, the alarm/monitoring system 114 may alert auser of the system 100A so that appropriate action may be taken, such asincreasing the oxygen levels given to the subject 130 or disconnectingthe subject 130 from the delivery system 100A.

With reference to FIG. 11, a system 100B is shown in which the activeagent source 107 is connected to two of the regulator valves 104 b, 104a. If the active agent source 107 is a liquid gas source, an optionalvaporizer 108 is provided to vaporize the liquid gas source. If theactive agent source 107 is gaseous (e.g., a high pressure gas), then thevaporizer 108 may be omitted. The active agent from the source 107 ismixed with the other gas sources 102 in the low pressure circuit 118 inamounts that are controlled by the flowmeters 106. The low pressurecircuit 118 includes a gas reservoir 109 that contains any overflow ofthe gas mixture as it flows to the breathing circuit 120. It should beunderstood that the active agent source 107 and/or any of the gassources 102 may be provided as a liquid gas source with a vaporizer. Theelements of the system 100B illustrated in FIG. 11 are essentially thesame as those described above with respect to FIG. 10 and will not bedescribed further.

Methods according to embodiments of the present invention which may becarried out using the systems 100, 100A, 100B are illustrated in FIG.12. A mixture of one or more breathable gas sources is provided (Block202). The breathable gas sources may be obtained from the gas sources102 as described with respect to FIGS. 9-11. A predetermined amount ofthe active agent is added to the gas mixture (Block 204), such as isshown with respect to the active agent source 107 in FIGS. 9-11. The gasmixture is administered to the subject 120 (Block 306). Exhaled gasesare ventilated and/or recycled (Block 208), for example, by thescavenger 112. Although the methods of FIG. 12 are described withrespect to the systems 100, 100A, 100B of FIG. 9-11, it should beunderstood that any suitable system or device may be used to carry outthe steps in FIG. 12.

2. Reduced Pressure Delivery System

Embodiments of a gas delivery system 300 are illustrated with respect toFIG. 13. The gas delivery system 300 is positioned on a subject 302. Thegas delivery system 300 is particularly suited to deliver an activeagent in a gas mixture to the tissue of a subject 302, for example,wound tissue.

The system 300 includes a reduced pressure chamber 304 having a screen306 that covers the treatment area of the subject 302. The reducedpressure chamber 304 is connected to a vacuum pump 310 by a pump outlet310 a. The reduced pressure chamber 304 includes an inlet 308 a and anoutlet 308 b, which are in turn connected to an active agent source 307.A controller 320 is connected to the active agent source 307 and thevacuum pump 310. Reduced pressure chambers and vacuum pump systems arediscussed in U.S. Pat. Nos. 5,645,081 and 5,636,643, the contents ofwhich are hereby incorporated by reference in their entireties.

The reduced pressure chamber 304 is configured to enclose an area of thesubject 302 to provide a fluid-tight or gas-tight enclosure to effecttreatment of the area with reduced or negative pressure and the activeagent source 307. The pressure chamber 304 can be affixed to the subject302 with a cover (not shown), such as a flexible, adhesive, fluidimpermeable polymer sheet. The cover can have an adhesive backing thatfunctions to cover the skin around the periphery of the area beingtreated and to provide a generally gas-tight or fluid-tight seal and tohold the chamber 304 in position.

The screen 306 is positioned over the treatment area of the subject 302.For example, if the treatment area of the subject 302 includes a wound,the screen 306 can be positioned over the wound to prevent itsovergrowth. The size and configuration of the screen 306 can be adjustedto fit the individual treatment area, and may be formed from a varietyof porous materials. The material should be sufficiently porous to allowoxygen any other gases, such as gases from the active agent source 307,to reach the treatment area. For example, the screen 306 can be in theform of an open-cell polymer foam, such as a polyurethane foam, which issufficiently porous to allow gas flow to and/or from the treatment area.Foams may be used that vary in thickness and rigidity, although it maybe desirable to use a spongy material for the patient's comfort if thepatient must lie upon the appliance during treatment. The foam may alsobe perforated to enhance gas flow and to reduce the weight of the system300. The screen 306 may be cut to an appropriate shape and size to fitwithin the treatment area, or alternatively, the screen 306 may besufficiently large to overlap the surrounding skin.

The vacuum pump 310 provides a source of suction within the reducedpressure chamber 304. The active agent source 307 provides an amount ofthe active agent to the reduced pressure chamber 304. The controller 320controls the amount of vacuum applied to the reduced pressure chamber304 by the vacuum pump 310 and the amount of the active agent that issupplied to the chamber 304 by the active agent source 307.

It should be understood that the controller 320 can apply a vacuumand/or the active agent in a substantially constant manner, cyclically,or using various fluctuations or patterns or any combination thereof. Insome embodiments, the active agent is supplied by the active agentsource 307 alternatively with the vacuum pumping action of the vacuumpump 310. That is, the controller 320 alternatively activates the vacuumpump 310 while deactivating the active agent source 307 and thenactivates the active agent source 307 while deactivating the vacuum pump310. The pressure in the reduced pressure chamber 304 is allowed tofluctuate. In other embodiments, a substantially constant pressure ismaintained by the vacuum pump 310 and the active agent source 307provides a substantially constant amount of active agent to the chamber304 in the reduced pressure environment. In some embodiments, asubstantially constant pressure is maintained by the vacuum pump 310 andthe amount of the active agent varies in a cyclical manner. In otherembodiments, the pressure in the reduced pressure chamber 304 is made tofluctuate by the vacuum pump 310, and the amount of active agentsupplied by the source 307 also fluctuates. The fluctuations of eitherthe vacuum pump 310 and the resulting pressure in the chamber 304 or theamount of active agent supplied by the source 307 may be cyclical or notcyclical.

Methods according to embodiments of the present invention that may becarried out using the system 300 are illustrated in FIG. 14. The chamber304 is positioned over the treatment area of the subject 302 (Block402). Pressure is reduced in the chamber 304 by the vacuum pump 310(Block 404). A predetermined amount of active agent from the activeagent source 307 is applied to the chamber (Block 406). Although themethods of FIG. 14 are described with respect to the system 300 of FIG.12, it should be understood that any suitable system or device may beused to carry out the steps in FIG. 14. For example, the outlet 308 bmay be omitted and the active agent may be supplied to the chamber 304by the single inlet 308 a. Other gases may also be added to the chamber304, for example, using a single inlet or an inlet and an outlet, suchas is illustrated with respect to the active agent source 307 and theinlet 308 a and the outlet 308 b. In some embodiments, the vacuum pump310 is attached to an additional collection container between the pump310 and the chamber 304 for collecting exudates from the treatment area,for example, as described in U.S. Pat. No. 5,636,643.

In some embodiments, the negative pressure gas delivery system 500, asdepicted in FIG. 22A, comprises an active oxygen antagonist source in acontainer 502, connected to a drape 504, via an inlet 506, by a conduit508. The drape forms a sealed envelope against a tissue site 510, whichmay a wound site. In some embodiments, the drape has an outlet 512 incommunication with a negative pressure source 514, via a conduit 516. Insome embodiments a waste canister 518, which may be a removable wastecanister, is in communication between the outlet and the negativepressure source. In some embodiments, a return outlet 520 is connectionwith the container 502 via a conduit 522. In some embodiments, as shownin FIG. 22B, a vaporizer 524 is interposed in the communication betweenthe container 502 and the drape 504.

The conduits may be flexible and may suitably be plastic of a likematerial hose. The negative pressure source 514, which may suitably be avacuum pump, is in some embodiments in fluid communication with theoutlet 512 via the conduit 516, for the promotion of fluid drainage, asis known in the art. In some embodiments, the waste canister 518 isplaced under vacuum through fluid communication to collect drainagefluid. Preferably a filter (not shown), which may be a hydrophobicmembrane filter, is interposed between the canister the negativepressure source to protect against contamination from drainage fluidssucked into the canister. In some embodiments, the drape 504 comprisesan elastomeric material, which may therefore accommodate pressurechanges over the tissue site area during intermittent operation of thenegative pressure source. In some embodiments, the periphery of thedrape is covered with a pressure sensitive adhesive, which may beacrylic adhesive, for sealing the drape over the tissue site.

Negative pressure gas delivery systems 300 and 500 as illustrated inFIG. 12 and FIG. 22A-B are useful for treating a variety of areas fortreatment, and, in particular, for treating wounds. Wounds that may betreated using the system 300 include infected open wounds, decubitusulcers, dehisced incisions, partial thickness burns, and various lesionsto which flaps or grafts have been attached. Treatment of a wound can becarried out by securing a gas delivery system to the treatment site aspreviously shown and described, maintaining a substantially continuousor cyclical reduced pressure within the reduced pressure chamber 304 andsupplying the active agent to the chamber 304 in a substantiallycontinuous or cyclical fashion until the wound has reached a desiredimproved condition. A selected state of improved condition may includeformation of granulation tissue sufficient for the attachment of a flapor graft, reduction of microbial infection in the wound, arrest orreversal of burn penetration, closure of the wound, integration of aflap or graft with the underlying wounded tissue, complete healing ofthe wound, or other stages of improvement or healing appropriate to agiven type of wound or wound complex. The gas delivery system may bechanged periodically, such as at 48 hrs intervals, during treatment,particularly when using a gas delivery system incorporating a screen onor in the wound. The method may be practiced using a negative or reducedpressure ranging from 0.01 to 0.99 atmospheres, or the method may bepracticed using a negative or reduced pressure ranging between 0.5 to0.8 atmospheres. The time period for use of the method on a wound may beat least 12 hrs, but can be, for example, extended for one or more days.There is no upper limit beyond which use of the method is no longerbeneficial; the method can increase the rate of closure up to the timethe wound actually closes. Satisfactory treatment of various types ofwounds may be obtained via the use of reduced pressures equivalent toabout 2 to 7 in. Hg below atmospheric pressure.

Supplying reduced pressure to the gas delivery system in an intermittentor cyclic manner, such as described above, may be useful for treatingwounds in the presence of the active agent. Intermittent or cyclicsupply of reduced pressure to a gas delivery system may be achieved bymanual or automatic control of the vacuum system. A cycle ratio, theratio of “on” time to “off” time, in such an intermittent reducedpressure treatment may be as low as 1:10 or as high as 10:1. A typicalratio is approximately 1:1 which is usually accomplished in alternating5 minute intervals of reduced pressure supply and non-supply.

A suitable vacuum system includes any suction pump capable of providingat least 0.1 pounds of suction to the wound, or up to three poundssuction, or up to fourteen (14) pounds suction. The pump can be anyordinary suction pump suitable for medical purposes that is capable ofproviding the necessary suction. The dimension of the tubinginterconnecting the pump and the reduced pressure appliance iscontrolled by the pump's ability to provide the suction level needed foroperation. A ¼ inch diameter tube may be suitable.

Embodiments of the present invention also include methods of treatingdamaged tissue, which include the steps of applying negative pressure toa wound and the active agent for a selected time and at a selectedmagnitude sufficient to reduce bacterial density in the wound. Openwounds are almost always contaminated with harmful bacteria. Generally abacterial density of 10⁵ bacterial organisms per gram of tissue isregarded as infected. It is generally accepted that at this level ofinfection, grafted tissue will not adhere to a wound. These bacteriamust be killed, either through the wound host's natural immune responseor through some external method, before a wound will close. Theapplication of negative pressure and active agent to a wound may reducethe bacterial density of the wound. It is believed that this effect maybe due to the bacteria's incompatibility with a negative pressureenvironment or the increased blood flow to the wound area in combinationwith exposure to the active agent, as blood brings with it cells andenzymes to destroy the bacteria. Methods according to embodiments of thepresent invention can be used to reduce bacterial density in a wound byat least half. In some embodiments, it can be used to reduce bacterialdensity by at least 1.000-fold or by at least 1,000,000-fold.

Embodiments of the present invention also include methods of treating aburn which include the steps of applying negative pressure and theactive agent to the burn over an area with predetermined reducedpressure and for a time sufficient to inhibit formation of a fullthickness burn. A partial thickness burn, one which has a surface layerof dead tissue and an underlying zone of stasis, is often sufficientlyinfected so that it will transform within 24-48 hrs into a fullthickness burn, one in which all epidermal structures are destroyed. Theapplication of negative pressure and an amount of the active agent tothe wound may prevent the infection from becoming sufficiently severe tocause destruction of the underlying epidermal structures. The magnitude,pattern, and duration of pressure application can vary with theindividual wound.

Embodiments of the present invention also include methods for enhancingthe attachment of living tissue to a wound which comprises the steps offirst joining the living tissue to the wound to form a wound-tissuecomplex, then applying a negative or reduced pressure of selectedmagnitude and an amount of the active agent to the wound-tissue complexover an area sufficient to promote migration of epithelia andsubcutaneous tissue toward the complex, with the negative pressure andexposure to the active agent being maintained for a selected time periodsufficient to facilitate closure of the wound. Attachment of livingtissue to a wound is a common procedure that can take many forms. Forexample, one common technique is the use of a “flap,” a technique inwhich skin tissue from an area adjacent to the wound is detached onthree sides but remains attached on the fourth, then is moved onto thewound. Another frequently used technique is an open skin graft in whichskin is fully detached from another skin surface and grafted onto thewound. The application of negative pressure and active agent to thewound-graft complex reduces bacterial density in the complex andimproves blood flow to the wound, thereby improving the attachment ofthe grafted tissue.

I. Other Apparatuses

Within certain embodiments of the invention, it may be desirable tosupplement the methods of the present invention for the treatment ofpatients who will be or have been subjected to trauma with the abilityto externally manipulate the core body temperature of the patient. Inthis regard, the core body temperature of a patient may be, incombination with the methods of the present invention, manipulated byinvasive or non-invasive routes. Invasive methods for the manipulationof core body temperature include, for example, the use of a heart-lungpump to heat or cool the patient's blood thus raising or cooling thepatient's core body temperature. Non-invasive routes to manipulate corebody temperature include systems and apparatuses that transfer heat intoor out of the patient's body.

J. Further Delivery Devices or Apparatuses

In some embodiments it is contemplated that methods or compositions willinvolve a specific delivery device or apparatus. Any method discussedherein can be implemented with any device for delivery or administrationincluding, but not limited, to those discussed herein.

For topical administration of active compounds of the invention may beformulated as solutions, gels, ointments, creams, suspensions, etc. asare well-known in the art. Systemic formulations may include thosedesigned for administration by injection or infusion, e.g.,subcutaneous, intravenous, intramuscular, intrathecal or intraperitonealinjection, as well as those designed for transdermal, transmucosal, oralor pulmonary administration.

For oral administration, the active compounds of the invention to beformulated as tablets, pills, dragees, capsules, liquids, gels, syrups,slurries, suspensions and the like, for oral ingestion by a patient tobe treated or oral liquid preparations such as, for example,suspensions, elixirs and solutions.

For buccal administration, the compositions may take the form oftablets, lozenges, etc. formulated in conventional manner. Otherintramucosal delivery might be by suppository or intranasally.

For administration directly to the lung by inhalation the compound ofinvention may be conveniently delivered to the lung by a number ofdifferent devices. For example,

Metered-Dose Inhalers (MDIs): a Metered Dose Inhaler (“MDI”) whichutilizes canisters that contain a suitable low boiling propellant, e.g.,dichlorodifluoromethane, trichlorofluoromethane,dichlorotetrafluoroethane, carbon dioxide or other suitable gas may beused to deliver the compound of invention directly to the lung. MDIdevices are available from a number of suppliers such as 3M Corporation(e.g., on the world wide web at3m.com/us/healthcare/manufacturers/dds/pdf/idd_valve_canister_brochure.pdf—),Nasacort from Aventis (e.g., world wide web atproducts.sanofi-aventis.us/Nasacort_HFA/nasacort_HFA.html—63 k—),Boehringer Ingelheim, (e.g., world wide webat.boehringer-ingelheim.com/corporate/home/download/r_and_d2003.pdf)Aerobid from Forest Laboratories, (e.g., world wide webat.frx.com/products/aerobid.aspx) Glaxo-Wellcome, (for example, on theworld wide web at.gsk.com/research/newmedicines/newmedicines_pharma.html) and ScheringPlough, (world wide web at.schering-plough.com/schering_plough/pc/allergy_respiratory.jsp).

Dry Powder Inhalers (DPIs): DPI devices typically use a mechanism suchas a burst of gas to create a cloud of dry powder inside a container,which may then be inhaled by the patient. DPI devices are also wellknown in the art and may be purchased from a number of vendors whichinclude, for example, Foradil aerolizer from Schering Corporation,(e.g., world wide web .spfiles.com/piforadil.pdf) Advair Diskus fromGlaxo-Wellcome. (e.g., world wide web atus.gsk.com/products/assets/us_advair.pdf—) A popular variation is themultiple dose DPI (“MDDPI”) system, which allows for the delivery ofmore than one therapeutic dose. MDDPI devices are available fromcompanies such as Plumicort Turbuhaler from AstraZeneca, (e.g., worldwide web at.twistclickinhale.com/GlaxoWellcome, (e.g., world wide web atus.gsk.com/products/assets/us_advair.pdf—) and Schering Plough, (e.g.,world wide web at.schering-plough.com/schering_plough/pc/allergy_respiratory.jsp). It isfurther contemplated that such devices, or any other devices discussedherein, may be altered for single use.

Electrohydrodynamic (EHD) aerosol delivery: EHD aerosol devices useelectrical energy to aerosolize liquid drug solutions or suspensions(see e.g., Noakes et al., U.S. Pat. No. 4,765,539; Coffee, U.S. Pat. No.4,962,885; Coffee, PCT Application, WO 94/12285; Coffee, PCTApplication, WO 94/14543; Coffee, PCT Application, WO 95/26234, Coffee,PCT Application, WO 95/26235, Coffee, PCT Application, WO 95/32807. EHDaerosol devices may more efficiently deliver drugs to the lung thanexisting pulmonary delivery technologies.

Nebulizers: Nebulizers create aerosols from liquid drug formulations byusing, for example, ultrasonic energy to form fine particles that may bereadily inhaled Examples of nebulizers include devices supplied bySheffield/Systemic Pulmonary Delivery Ltd. (See, Armer et al., U.S. Pat.No. 5,954,047; van der Linden et al., U.S. Pat. No. 5,950,619; van derLinden et al., U.S. Pat. No. 5,970,974), Intal nebulizer solution byAventis, (e.g., world wide web at.fda.gov/medwatch/SAFETY/2004/feb_PI/Intal_Nebulizer_PI.pdf).

For administration of a gas directly to the lungs by inhalation variousdelivery methods currently available in the market for delivering oxygenmay be used. For example, a resuscitator such as an ambu-bag may beemployed (see U.S. Pat. Nos. 5,988,162 and 4,790,327). An ambu-bagconsists of a flexible squeeze bag attached to a face mask, which isused by the physician to introduce air/gas into the casualty's lungs.

A portable, handheld medicine delivery device capable producing atomizedagents that are adapted to be inhaled through a nebulizer by a patientsuffering from a respiratory condition. In addition, such deliverydevice provides a means wherein the dose of the inhaled agent can beremotely monitored and, if required altered, by a physician or doctor.See U.S. Pat. No. 7,013,894. Delivery of the compound of invention maybe accomplished by a method for the delivery of supplemental gas to aperson combined with the monitoring of the ventilation of the personwith both being accomplished without the use of a sealed face mask suchas described in U.S. Pat. No. 6,938,619. A pneumatic oxygen conservingdevice for efficiently dispensing oxygen or other gas used duringrespiratory therapy such that only the first part of the patient'sbreath contains the oxygen or other therapeutic gas. (See U.S. Pat. No.6,484,721). A gas delivery device is used which is triggered when thepatient begins to inhale. A tail of gas flow is delivered to the patientafter the initial inhalation timed period to prevent pulsing of gasdelivery to the patient. In this manner gas is only delivered to thepatient during the first portion of inhalation preventing gas from beingdelivered which will only fill the air passageways to the patient'slungs. By efficiently using the oxygen, cylinder bottles of oxygen usedwhen a patient is mobile will last longer and be smaller and easier totransport. By pneumatically delivering the gas to the patient nobatteries or electronics are used.

All the devices described here may have an exhaust system to bind orneutralize the compound of invention.

Transdermal administration of the compound of the invention can beachieved by medicated device or patch which is affixed to the skin of apatient. The patch allows a medicinal compound contained within thepatch to be absorbed through the skin layers and into the patient'sblood stream. Such patches are commercially available as Nicoderm CQpatch from Glaxo Smithkline, (world wide web atnicodermcq.com/NicodermCQ.aspx \) and as Ortho Evra from Ortho-McNeilPharmaceuticals, (world wide webat.ortho-mcneilpharmaceutical.com/healthinfo/womenshealth/products/orthoevra.html).Transdermal drug delivery reduces the pain associated with druginjections and intravenous drug administration, as well as the risk ofinfection associated with these techniques. Transdermal drug deliveryalso avoids gastrointestinal metabolism of administered drugs, reducesthe elimination of drugs by the liver, and provides a sustained releaseof the administered drug. Transdermal drug delivery also enhancespatient compliance with a drug regimen because of the relative ease ofadministration and the sustained release of the drug.

Other modifications of the patch include the Ultrasonic patch which isdesigned with materials to enable the transmission of ultrasound throughthe patch, effecting the delivery of medications stored within thepatch, and to be used in conjunction with ultrasonic drug deliveryprocesses(see U.S. Pat. No. 6,908,448). Patch in a bottle (U.S. Pat. No.6,958,154) includes a fluid composition, e.g., an aerosol spray in someembodiments, that is applied onto a surface as a fluid, but subsequentlydries to form a covering element, such as a patch, on a surface of ahost. The covering element so formed has a tack free outer surfacecovering and an underlying tacky surface that helps adhere the patch tothe substrate.

Another drug delivery system comprises one or more ball semiconductoraggregations and facilitating release of a drug stored in a reservoir.The first aggregate is used for sensing and memory, and a secondaggregation for control aspects, such as for pumping and dispensing ofthe drug. The system may communicate with a remote control system, oroperate independently on local power over a long period for delivery ofthe drug based upon a request of the patient, timed-release undercontrol by the system, or delivery in accordance with measured markers.See U.S. Pat. No. 6,464,687.

PUMPS and Infusion Devices: An infusion pump or perfusor infuses fluids,medication or nutrients into a patient's circulatory system. Infusionpumps can administer fluids in very reliable and inexpensive ways. Forexample, they can administer as little as 0.1 mL per hour injections(too small for a drip), injections every minute, injections withrepeated boluses requested by the patient, up to maximum number per hour(e.g. in patient-controlled analgesia), or fluids whose volumes vary bythe time of day. Various types of infusion devices have been describedin the following patent applications before the United States Patent andTrademark Office. These include but are not limited to U.S. Pat. No.7,029,455 U.S. Pat. No. 6,805,693, U.S. Pat. No. 6,800,096, U.S. Pat.No. 6,764,472, U.S. Pat. No. 6,742,992, U.S. Pat. No. 6,589,229, U.S.Pat. No. 6,626,329, U.S. Pat. No. 6,355,019, U.S. Pat. No. 6,328,712,U.S. Pat. No. 6,213,738, U.S. Pat. No. 6,213,723, U.S. Pat. No.6,195,887, U.S. Pat. No. 6,123,524 and U.S. Pat. No. 7,022,107. Inaddition, infusion pumps are also available from Baxter InternationalInc. (world wide web at.baxter.com/products/medication_management/infusion_pumps/), AlarisMedical Systems (world wide web atalarismed.com/products/infusion.shtml) and from B Braun Medical Inc.(world wide web at bbraunusa.com/index.cfm?uuid=001AA837D0B759A1E34666434FF604ED).

Oxygen/Gas bolus delivery device: Such a device for delivering gas toChronic Obstructive Pulmonary Disease (COPD) patients is a availablefrom Tyco Healthcare (world wide web at.tycohealth-ece.com/files/d0004/ty_zt7ph2.pdf). It can also be used todeliver the compound of invention. The above device is cost-effective,lightweight, inconspicuous and portable.

“Patch in a bottle” (U.S. Pat. No. 6,958,154) includes a fluidcomposition, e.g., an aerosol spray in some embodiments, that is appliedonto a surface as a fluid, but subsequently dries to form a coveringelement, such as a patch, on a surface of a host. The covering elementso formed has a tack free outer surface covering and an underlying tackysurface that helps adhere the patch to the substrate.

Implantable Drug Delivery System: Another drug delivery system comprisesone or more ball semiconductor aggregations and facilitating release ofa drug stored in a reservoir. The first aggregate is used for sensingand memory, and a second aggregation for control aspects, such as forpumping and dispensing of the drug. The system may communicate with aremote control system, or operate independently on local power over along period for delivery of the drug based upon a request of thepatient, timed-release under control by the system, or delivery inaccordance with measured markers. See U.S. Pat. No. 6,464,687.

The contents of each of the cited patents and web addresses discussed inthis section are hereby incorporated by reference.

VIII. Combination Therapies

The compounds and methods of the present invention may be used in thecontext of a number of therapeutic and diagnostic applications. In orderto increase the effectiveness of a treatment with the compositions ofthe present invention, such as oxygen antagonists or other activecompounds, it may be desirable to combine these compositions with otheragents effective in the treatment of those diseases and conditions(secondary therapy). For example, the treatment of stroke (antistroketreatment) typically involves an antiplatelet (aspirin, clopidogrel,dipyridamole, ticlopidine), an anticoagulant (heparin, warfarin), or athrombolytic (tissue plasminogen activator).

Various combinations may be employed; for example, anactive compound,such as H₂S, is “A” and the secondary therapy is “B”:

A/B/A B/A/B B/B/A A/A/B A/B/B B/A/A A/B/B/B B/A/B/B B/B/B/A B/B/A/BA/A/B/B A/B/A/B A/B/B/A B/B/A/A B/A/B/A B/A/A/B A/A/A/B B/A/A/A A/B/A/AA/A/B/A

Administration of the oxygen antagonists and/or other active compoundsof the Spresent invention to biological matter will follow generalprotocols for the administration of that particular secondary therapy,taking into account the toxicity, if any, of the oxygen antagonist (orother active compound) treatment. It is expected that the treatmentcycles would be repeated as necessary. It also is contemplated thatvarious standard therapies, as well as surgical intervention, may beapplied in combination with the described therapies.

IX. Examples

The following examples are included to demonstrate preferred embodimentsof the invention. It should be appreciated by those of skill in the artthat the techniques disclosed in the examples which follow representtechniques discovered by the inventor to function well in the practiceof the invention, and thus can be considered to constitute preferredmodes for its practice. However, those of skill in the art should, inlight of the present disclosure, appreciate that many changes can bemade in the specific embodiments which are disclosed and still obtain alike or similar result without departing from the spirit and scope ofthe invention.

Example 1 Preservation of Nematodes in Carbon Monoxide

The atmosphere contains 210,000 ppm oxygen. Exposure to low levels ofoxygen, or hypoxia, results in cellular damage and death in humans. Inthe nematode, C. elegans, oxygen concentrations between 100 ppm and 1000ppm are also lethal. By critically studying the response of nematodes toa range of oxygen tensions, it was found that oxygen concentrationsbelow 10 ppm and above 5000 ppm are not lethal. In 10 ppm oxygenbalanced with nitrogen, nematodes enter into a state of reversiblesuspended animation in which all aspects of animation observable underthe light microscope ceases (Padilla et al., 2002). In oxygenconcentrations of 5000 ppm (balanced with nitrogen) and above, nematodesprogress through their life cycle normally. In a search for drugs thatprotect nematodes against hypoxic damage, carbon monoxide was tested.

To achieve specific atmospheric conditions the following apparatus wasused: a glass syringe barrel having a tip with a locking device such asa LUER-LOK with the large opening of the barrel sealed with acustom-machined steel and rubber fitting to make an airtight seal waslocked to via locking device to the inlet port of an environmentalchamber having an inlet and an outlet port each fitted with a lockingdevices such as a LUER-LOK fitting. A defined gas was humidified andprovided to the environmental chamber by first venting the gas from acompressed tank (Byrne Specialty Gas, Seattle, Wash.) through a gaswashing bottle (500 ml Kimex) filled with double distilled water. Thegas washing bottle was connected to the environmental chamber past agas-flow meter. A gas flow meter was used to provide a regulated 70cc/min flow through the environmental chamber throughout the 24 hrincubation.

To test whether induced, reversible stasis could be achieved in C.elegans nematodes, 2-cell C. elegans embryos, L3 larvae or adultnematodes were collected and exposed to either an environment ofeffectively 100% CO, an environment of 100% N₂, an environmentcomprising 500 ppm oxygen balanced with carbon monoxide, or toenvironments comprising 100, 500 or 1000 ppm oxygen balanced withnitrogen at room temperature. Nematodes were visualized usingdifferential interference contrast microscopy (also known as Nomarskioptics). Images were collected and analyzed using NIH image and AdobePhotoshop 5.5. Embryos are approximately 50 μm in length.

Results of these experiments showed that 100% carbon monoxide was notlethal and induced reversible suspended animation. Nematodes did notsurvive 500 ppm oxygen balances with nitrogen, however, those treatedwith 500 ppm oxygen balanced with carbon monoxide entered into suspendedanimation and survived. See below:

Example 2 Preservation of Human Skin in Carbon Monoxide

Carbon monoxide is extraordinarily toxic to humans because it stronglycompetes with oxygen for binding to hemoglobin, the primary moleculethat distributes oxygen to tissues. The fact that nematodes, which donot have hemoglobin, are resistant to carbon monoxide and even protectedagainst hypoxic damage by this drug suggested the possibility thatcarbon monoxide would protect against hypoxic damage in human tissue insituations where blood is not present, such as in tissue transplant orblood free surgical fields. To tested this hypothesis using human skin.

Three human foreskins were obtained for this purpose. The foreskintissue was preserved in keratinocyte growth medium (KGM) containinginsulin, EGF (0.1 ng/ml), hydrocortisone (0.5 mg/ml) and bovinepituitary extract (approx. 50 micrograms/ml of protein). Foreskins wererinsed in PBS, and excess fatty tissue was removed. Each foreskin samplewas divided into 2 equal pieces. Each piece was placed into a separatecontainer containing a solution of PBS with 24 mg/ml of Dispase II (fromBacillus Polymyxa EC 3.4.24.4:Roche Diagnostics Corp., Indianapolis,Ind.). One container (containing a foreskin piece in PBS with DispaseII) was kept in a humid chamber in a fume hood. The other container(with the other half of the foreskin in PBS with Dispase II) was placedin the same fume hood in an environmental chamber perfused withhumidified 100% CO. Both samples were maintained at room temperature for24 hrs. Methods used to establish defined atmospheric conditions wereidentical to those used in Example 1.

Following the 24 hr exposure to normoxia or 100% CO, keratinocytes wereisolated from the foreskins according to the method described by Boyceet al. (1983; 1985; each of which is incorporated herein by reference inits entirety). Briefly, the epidermis from each foreskin sample wasremoved to a fresh dish containing PBS. The epidermis was minced andhomogenized prior to incubation in 3 ml of 0.05% Trypsin, 1 mM EDTA for5 minutes, at room temperature, to separate basal cells from theepidermis. After incubation, 6 ml of 400 Hg/ml (micrograms per ml)Soybean Trypsin Inhibitor, 1 mg/ml BSA was added and the samples werecentrifuged at 900 RPM. The supernatant from each sample was discardedand the sample pellets were resuspended in 10 ml of KGM. Each sample wassplit into two 10 cm plates each of which contained 5 ml KGM and 100 μlof HEPES pH 7.3 (N-2-hydroxyethylpiperazine-N′-2-ethane sulfonic acid).The plates were incubated in a 37° C. incubator perfused with 95% roomair, 5% carbon dioxide for five days.

Cells were inspected visually using an inverted phase contrastmicroscope. All three of the keratinocyte populations exposed tonormoxia showed little or no growth. All three of the keratinocytepopulations exposed to 100% CO showed significant growth. Quantitationof the number of viable keratinocytes as judged by colony formation wasquantified for two of the three foreskins. See FIG. 1.

TABLE 1 Quantitation of Colony Formation Foreskin Atmosphere Totalcolonies 1 100% 542 colonies (many of which were very CO large) 1Normoxia 2 colonies (both small) 2 100% CO 780 colonies (many of whichwere very large) 2 Normoxia 0 colonies

Example 3 Further Preservation Experiments with Nematodes

The following example contains information that overlaps and extends theinformation disclosed in Example 1.

A. Materials and Methods

Environmental chambers and apparati. Oxygen deprivation experiments werecarried out using a custom atmospheric chamber designed by W. VanVoorhies (Van Voorhies et al., 2000). The chamber is a 30 mL glasssyringe (Fisher #14-825-10B) fitted with a custom steel stopper that islined with two viton o-rings to ensure a tight seal. The stopper isbored through and has a steel lure lock on the exterior face so that ahose carrying compressed gas can be attached. A defined gas mixture isdelivered to the chamber at a constant pressure and flow rate fromcompressed tanks by passing first through a rotometer (Aalborg,flow-tube number 032-41ST) or mass flow controller (Sierra Instruments#810) to monitor flow rate and then through a 500 ml gas washing bottle(Fisher #K28220-5001) containing 250 ml water to hydrate the gas. ¼″ ODnylon (Cole-Parmer #P-06489-06) or FEP (Cole-Parmer #A-06450-05) tubingwas used and connections between tubing and the regulators and betweenthe tubing and the rotometers were made with brass John-Guest-typefittings (Byrne Gas). All other connections were made with eithermicroflow quick-connect fittings (Cole-Parmer #A-06363-57, #A-06363-52)or standard lure fittings (Cole-Parmer #A-06359-37, #A-06359-17).

Viability of nematodes in hypoxia. Bristol strain N2 were continuouslymaintained at 20° C. with care taken to ensure the population did notstarve. Log-phase, adult C. elegans were picked into a drop of sterilewater containing 100 μg/ml ampicillin, 15 μg/ml tetracycline and 200μg/ml streptomycin on a glass plate. Adults were chopped with a razorblade and 2-cell embryos were picked using a mouth pipet. 30-60 2-cellembryos were transferred to a small glass boat (custom made to fitatmospheric chambers, Avalon Glass Works, Seattle Wash.) filled with 3ml of 1% agarose in M9. Boats were then placed into a humid chamber for2 hours to allow the embryos to age and then placed into theenvironmental chamber. The environmental chambers were continuouslyperfused at room temperature with either pure N₂ (grade 4.5), 100 ppmO₂/N₂, 500 ppm O₂/N₂, 1000 ppm O₂/N₂, or 5000 ppm O₂/N₂ at 70 cc/min for24 hrs. Following exposure, agarose chunks containing the embryos werecut out of the boat and placed with embryos facing up onto amedium-sized NGM plate seeded with E. coli (OP50). Embryos were scoredfor hatching 24 hours after exposure and hatched L1's were transferredto the surface of the NGM plate and followed to adulthood. Animals thatcould not be accounted for were dropped from the total. All gases weresupplied by Byrne Gas (Seattle, Wash.). The pure N₂ was guaranteed tocontain less than 10 ppm impurities and all O₂/N₂ mixtures werecertified to ±2% of the oxygen content (e.g., 100 ppm O₂/N₂ wascertified to contain between 98 ppm O₂ and 102 ppm O₂). Parts permillion to kPa conversion was based on 1 million parts=101 kPa at 1atmosphere.

Viability of nematodes in carbon monoxide based atmospheres. 30-60embryos were harvested from continuously maintained Bristol N2 andhif-2(ia04) strains as described above. Environmental chambers werecontinuously perfused at room temperature with pure CO (grade CP) or 500ppm O₂/CO at 70 cc/min for 24 hrs. To achieve 2500 ppm O₂/CO or 2500 ppmO₂/N₂, 5000 ppm O₂₁N₂ was mixed at a 1:1 ratio with either pure CO orpure N₂ using two mass flow controllers (Sierra Instruments 810) toprecisely monitor flow. Each gas was delivered into a 3-way valve(Cole-Parmer #A-30600-23) at 50 cc/min and the resulting mixture wasthen passed through a gas washing bottle and into an environmentalchamber throughout the 24 hour exposure. All gases were supplied byByrne Gas (Seattle, Wash.). The 500 ppm O₂/CO mixture was certified to+2% of the oxygen content and contained 7000 ppm N₂ to ensure aconsistent O₂/CO ratio throughout the use of the tank.

Cell biological analysis. To determine the extent of developmentalprogression in nitrogen-based atmospheres (Table 2), 2-cell embryos wereexposed to various degrees of hypoxia as described above and were eitherimmediately photographed, or photographed following a 12 hr recoveryperiod in a humid chamber. To determine whether embryos arrested incarbon monoxide-based atmospheres, 2-cell embryos were aged in room airfor two hours and were either photographed immediately or put into 100%carbon monoxide or 0.05 kPa O₂/CO for 24 hours and photographedimmediately following the exposure. In all cases, DIC microscopy wasdone by placing embryos under a cover slip on a thin 1% agarose pad andviewing on a Zeiss axioscope. Photographs were taken using RS Image andAdobe Photoshop software.

B. Results

HTF-1 has been previously reported to be required in C. elegans in mildhypoxia (0.5 kPa O₂ (Padilla et al., 2002) and 1 kPa O₂ (Jiang et al.,2001)) and suspended animation is known to be possible in anoxia (>0.001kPa O₂) (Padilla et al., 2002). To precisely define the ranges in whicheach of these responses are active, the viability of wild-type C.elegans embryos was determined following exposure to various oxygentensions between mild hypoxia and anoxia for 24 hrs. Embryos exposed toanoxia entered suspended animation as previously reported, and thussurvived the exposure with high viability. Embryos in 0.5 kPa O₂remained animated throughout the exposure and also survived with highviability. However, embryos exposed to an intermediate range of oxygentensions between mild hypoxia and anoxia (0.1 kPa O₂ to 0.01 kPa O₂)surprisingly did not survive (FIG. 2).

Embryos did not hatch during exposure to this intermediate range ofhypoxia, indicating that they did not successfully execute the HIF-1mediated response. To determine if they appeared suspended, it wasexamined whether embryos in this intermediate range arrestedembryogenesis during the exposure. Embryos in lethal oxygen tensions didnot arrest embryogenesis, and increased amounts of oxygen correlatedwith an increase in the extent of developmental progression in theembryo (Table 2). Upon reoxygenation, the majority of these embryosfailed to hatch and many of those that did hatch arrested as abnormalL1s. These data show that this intermediate range of hypoxia is a uniquestress in which oxygen levels are neither sufficiently high tofacilitate continued animation nor sufficiently low to induce suspendedanimation.

Based on these findings, it was hypothesized that if carbon monoxide, acompetitive inhibitor of oxygen binding, could induce suspendedanimation in the presence of low levels of oxygen, it would provideprotection against this lethal range of hypoxia. To examine thispossibility, the viability of C. elegans embryos in variousconcentrations of carbon monoxide was first determined. Despite thetoxic effects that high levels of carbon monoxide can have in somesystems, C. elegans embryos was found to be remarkably tolerant to awide range of carbon monoxide tensions. In fact, C. elegans embryos canwithstand a continuous exposure to 101 kPa CO (100% CO) for 24 hrs withhigh viability (81.5% survival to adulthood, FIG. 3). Notably, in 101kPa CO, embryos did not progress through embryogenesis during theexposure, indicating that they entered into suspended animation. To testwhether carbon monoxide could protect embryos in the presence of lethaloxygen tensions, the viability of embryos exposed to 0.05 kPa O₂balanced with carbon monoxide was determined. In contrast to embryosexposed to 0.05 kPa O₂ balanced with N₂ (most of which do not survive),these embryos recovered with 96.2% viability to adulthood (FIG. 3).Moreover, like embryos treated with 101 kPa CO, embryos in 0.05 kPa O₂balanced with carbon monoxide arrested embryogenesis, indicating thatthey entered into suspended animation. Therefore, carbon monoxide canprotect against hypoxic damage in the presence of lethal oxygen tensionsby inducing suspended animation.

To further examine the range of oxygen tensions that can be protected byexcess carbon monoxide, embryos lacking HIF-1 function (the hif-1(ia04)strain) were used to address whether protection against hypoxic damagewas also possible in mild hypoxia. After testing various oxygen tensionsbetween 0.1 kPa ° 2 and 1 kPa ° 2 balanced with nitrogen, it was foundthat the maximal requirement for HIF-1 was in 0.25 kPa ° 2 balanced withnitrogen. In this atmosphere, wild-type embryos progress normallythrough development and exhibit high viability, but hif-1(ia04) embryosdo not complete embryogenesis and exhibit 100% lethality (Table 3).Therefore, it was examined whether carbon monoxide could protecthif-1(ia04) embryos in 0.25 kPa 2. In 0.25 kPa O₂ balanced with carbonmonoxide, both wild-type and hif-1 (ia04) embryos entered into suspendedanimation and survived the exposure with high viabilities (78.7% and84.0% survival to adulthood, respectively) (Table 3). Thus, theinduction of suspended animation by carbon monoxide is possible atoxygen tensions as high as 0.25 kPa ° 2, and carbon monoxide can protectagainst mild hypoxia, even in the absence of HIF-1 function.

TABLE 2 Quantitation of developmental progression in hypoxia Percent ofRange of embryos within embryogenesis Atmosphere range (min post 2-cellstage) N >0.001 kPa O₂/N₂  100% ± 0.0  20-40 min 35  0.01 kPa O₂/N₂92.9% ± 6.0  40-80 min 115  0.05 kPa O₂/N₂ 97.7% ± 2.0 100-140 min 108  0.1 kPa O₂/N₂ 91.4% ± 1.3 300-340 min 60Wild-type 2-cell embryos were placed into various degrees of hypoxia for24 hrs and scored for the extent to which they progressed throughembryogenesis. Exposure to atmospheres containing increased amounts ofoxygen resulted in increased progression through embryogenesis. Thepercent of embryos that arrested within a given 20-40 minute range ofembryogenesis was determined. Data are the result of 3 independentexperiments.

TABLE 3 Carbon monoxide protects hif-1 embryos against mild hypoxia 0.25kPa O₂/N₂ n 0.25 kPa O₂/CO N N2 94.2% ± 1.2 49 78.7% ± 21.9 109hif-1(ia04)  0.0% ± 0.0 68 83.9% ± 13.8 108Viabilities to adulthood were assayed following exposure to 24 hrs of0.25 kPa O₂/N₂ or 0.25 kPa O₂/CO in wild-type and hif-1(ia04) embryos.All data points are the result of at least 3 independent experiments andworms that could not be accounted for were dropped from the total.Viability of Nematodes in Response to hypothermia.

Viability of nematodes is also temperature sensitive, with 100% of apopulation being dead after a 24 hr exposure to cold temperature (4° C.;FIG. 15). However, if the nematodes are induced into stasis byequilibration into anoxic conditions (<10 ppm oxygen) for 1 hr prior tothe temperature drop, a substantial proportion of them survive after a24 hr exposure to 4° C. (FIG. 15). In this experiment, the nematodeswere kept in stasis during the period of hypothermia, and for one hourafter they have been returned to room temperature. Anoxic conditions(pure N₂), growth conditions, and viability measurements are describedbelow.

Example 4 Reduction of Core Body Temperature and Respiration in Mice

A. Materials and Methods

Implantation of telemetry devices. Female C57BL/6J mice (JacksonLaboratories—Bar Harbor, Me.) were implanted with telemetry devices(PDT-4000 HR E-Mitter—MiniMitter Inc.—Bend, Oreg.) according to standardprotocol provided by the manufacturer. Mice were allowed to recover forseveral weeks to permit body temperature and heart rate signals tostabilize. Core body temperature, heart rate, and movement of the micewere continuously monitored via the telemetry devices and recorded usingVitalView software (provided by MiniMitter). Ambient temperature wasmonitored using a HOBO (Onset Computer Corp.—Pocasset, Mass.) and thedata analyzed using BoxCar software (provided by Onset Computer Corp.).

Exposure of Mice to Regulated Atmosphere. Each mouse was exposed to 1L/min of either (a) an atmosphere containing 500 ppm H₂S balancednitrogen (Byrne Specialty Gas—Seattle, Wash.) mixed with room air (usinga 3 channel gas proportioner meter from Aalborg—Orangeburg, N.Y.) togive a final concentration of 80 ppm H₂S and 17% O₂, or (b) anatmosphere of nitrogen mixed with room air to give a final concentrationof 17% O₂. H₂S and O₂ measurements were taken using an Innova GasTech GTseries portable gas monitor (Thermo Gas Tech—Newark, Calif.).

Prior to and during exposure to testing in regulated and unregulatedatmospheres, the mice were placed in a gassing chamber comprising aglass cage (with drinking water and no food) fitted with import andexport tubes of FEP tubing from Cole-Parmer (Vernon Hills, Ill.) forintroduction and venting of the atmosphere. The cage was sealed with alid using Dow Corning silicone vacuum grease (Sigma—St. Louis, Mo.). Thegas from each cage was vented through the export tube into the chemicalhood. To ensure that the system was gas-tight, a GasTech GT portablemonitor was used to detect leaks.

Respirometry. In some experiments, the consumption of oxygen wasmeasured by use of a PA-10a O₂ analyzer (Sable Systems) which was usedaccording to manufacturers instructions. Similarly, the carbon dioxidebeing produced by the animals was monitored using a LI-7000 CO₂/H₂Oanalyzer (Li-Cor company) used according to the manufacturersinstructions. These instruments were placed in line with theenvironmental chambers such that they sample the gas import and exporttubing.

Regulation of Ambient Temperature. Mice were housed in a Shel Lab lowtemperature diurnal illumination incubator (Sheldon ManufacturingInc.—Cornelius, Oreg.) to regulate both temperature and light cycle (8AM lights on, 8 PM lights off) for the mice. Mice were exposed toregulated atmosphere as described above. When the mice were exposed tothe regulated atmosphere, the temperature inside the incubator wasdropped to the desired temperature, for example, to 10° C. or 15° C. Themice were maintained in the regulated atmosphere and at the loweredtemperature for six hours. The atmosphere in the gassing chamber wasreplaced with room air and the mice were returned to normal roomtemperature (22° C.) and allowed to recover.

B. Results

Baseline Data. To determine the response of mice to sub-lethal doses ofhydrogen sulfide, the inventor first established baselines of coretemperature, heart rate and movement by recording data over a one-weekperiod from four mice with implanted transceivers in the incubator heldat ambient temperature and perfused with room air. The baseline datademonstrated that the mice have a circadian rhythm with peak of activityin the evening just after the lights are turned off, and in the earlymorning just before the lights are turned on. The core temperaturevaried from a high of 37° C. during their active periods to a low of33.5° C. during their inactive periods. The heart rate varied from 750bpm (beats per minute) during their active periods to 250 bpm duringtheir inactive periods. Heart rate is likely to be correlated with coretemperature (higher temp higher heart rate). Likewise gross motormovement was highest during the evening and just before dawn.

Exposure of Mice to Regulated Atmospheres at Room Temperature. The firsttrial of the exposure of a mouse to hydrogen sulfide involved firstplacing the mouse into the gassing chamber held at 27° C. in theincubator for one hour. After the hour, the chamber was perfused with 80ppm as generally described above and the temperature of the incubatorwas lowered to 18° C. for the duration of the experiment. While noimmediate changes in heart rate and gross motor movement were detected,a dramatic decrease in core temperature was observed. The experiment wasallowed to proceed for 90 min. during which time the core temperaturedropped to 28.6° C.—five degrees below the lowest recording for any ofthe four mice in the baseline study described above. During recoveryafter the chamber was perfused with room air, the inventor noticed thatthe animal at first was relatively immobile (easy to catch); howeverwithin 60 min. it had returned to a normal range of core temperature andactivity. A second mouse was exposed to the same protocol; however thistime the gassing at 80 ppm was conducted for 3 hrs. During this time,the inventor noted that heart rate dropped significantly from 600 bpm to250 bpm, gross motor movement showed almost no activity, and the coretemperature dropped to 18.6° C.

Changes in respiration accompany the drop in core temperature. Exposureof the mice to 80 ppm H₂S results in decreased metabolic rate as well,as determined by measuring oxygen consumption and carbon dioxideproduction. For example, a mouse that had core temperature and carbondioxide production measured simultaneously, demonstrated a rapidreduction in carbon dioxide production preceding the drop in coretemperature of the animal (FIG. 4A). The approximately three-foldreduction in carbon dioxide production established a new baseline inapproximately 5 minutes after the exposure to H₂S.

Table 4 shows results from an experiment with concurrent measurements ofO₂ and CO₂ concentrations from mice exposed to room air that had had theCO₂ scrubbed (hence the 0 values for controls), with or without H₂S (80ppm). Measurements were over a period of 15 minutes, with the mice in a0.5 L sealed environmental chamber with flow rates of 500 cc/min.Consumption of oxygen is obtained by subtracting the oxygenconcentration when the mouse is present, from the control when the mouseis absent. Likewise, production of carbon dioxide is obtained bysubtracting the carbon dioxide concentration when the mouse is presentfrom the control when the mouse is absent. RQ stands for respiratoryquotient, and is equal to the ratio of carbon dioxide produced to oxygenproduced. This result demonstrates, a 2-3 fold drop in oxygenconsumption in the presence of H₂S, as well as a 3-4 fold drop in carbondioxide production. The change in the respiratory quotient reflects thedisparity oxygen consumption and carbon dioxide production by the micein the presence or absence of the H₂S.

TABLE 4 H₂S exposure inhibits respiration in mice. Mouse present H₂Spresent [O₂] ppm [CO₂] ppm RQ − − 207,000 0 + − 203,600 2800Consumption, production 3,400 2800 0.82 − + 166,200 0 + + 164,900 750Consumption, production 1300 750 0.58

The different parameters of stasis (reduction in oxygen consumption,decrease in carbon dioxide production or decrease in motility) can beassessed by a variety of assays and techniques. For example, probablythe easiest way to measure the induction of stasis in mice administeredH₂S is through observation of their breathing. Indeed, this encompassesall three parameters in that it is indicative of decreased oxygenconsumption, carbon dioxide production and motility. A normal mouse inroom air at standard conditions will take approximately 200 breaths perminute. If H₂S is administered to the mouse at 80 ppm, and the coretemperature is dropped to 15° C., breathing is decreased at least anorder of magnitude to somewhere between 1-10 breaths per minute. Infact, a mouse was observed under these conditions that did not take abreath for a period greater than an hour, indicating that deep levels ofstasis are attainable. Thus, this represents at least about a 1-20-folddecrease in cellular respiration (i.e, oxygen consumption and carbondioxide production).

Exposure of Mice to Regulated Atmospheres at Reduced AmbientTemperatures. To begin to define the limits of the capacity for hydrogensulfide to reduce the activity in mice, the inventor conducted severalexperiments in which a non-telemetry mouse was used, followed byexposure of a mouse bearing telemetry to acquire the data. The firstexperiment was to subject a non-telemetry mouse to a regulatedatmosphere of H₂S at 80 ppm in a reduced cabinet temperature of 10° C.essentially as described in Materials and Methods were as above exceptthat the mouse was placed in the gassing chamber for one hour at 27° C.prior to exposure to the gas and reduction in ambient temperature. Thenon-telemetry mouse did well in this treatment, and recovered activitywithin approximately 90 min. after removal from the gassing chamber. Thetelemetry mouse was subjected to the same conditions also did well, andshowed decreased core temperature to approximately 12.5° C. The inventorwas unable to accurately determine this temperature because theelectronics failed at 15.3° C. The temperature drop to 12.5° C. istherefore an estimation based on the slope of the drop prior to failureand the time the animal remained in the chamber after failure of theelectronics.

Because of the limitation of the equipment, the inventor next testedeach of the four telemetry mice for a 6 hr period in the gassing chamberwith a regulated atmosphere containing approximately 80 ppm hydrogensulfide or with room air essentially as described above. The temperatureof the incubator was reduced at initiation of the experiment (exposureto the regulated atmosphere, or time 0 for the mice exposed to room air)to a constant 15° C. At the end of the six-hour period, the mice werereturned to an atmosphere of room air and an ambient temperature of 22°C. as generally described above. There was a clear decrease in core bodytemperature in all four mice that was dependent on the use of 80 ppmhydrogen sulfide (FIG. 4B). There was also a marked drop in heart rateand gross motor movement associated with the decrease in temperature.The mice were maintained for 4 weeks with no apparent change in thebehavior of the animals.

Example 5 Murine Studies on Reduction of Radiation Injury

A. Scientific Rationale

While aspects of the radiation injury model can and have been evaluatedin cell culture, to test the ability of an experimental drug to affectthe injury and healing process requires inclusion of all of the responsesystems that are affected. At this point in time, the only way toachieve that is in a whole animal. The inventor is proposing the use ofmice for such studies as the most appropriate model. The C57BL/6 micehave been selected for study because this strain of mouse is readilysusceptible to radiation lung injury, the level of radiation that istolerated in this strain has been established, and the inventor hasrecently shown that H₂S decreases the core temperature of this mousestrain.

Two identical experiments are planned under this protocol. Eachexperiment will investigate the efficacy of H₂S-induced hypothermia onthe development of radiation induced lung injury. Ten mice per groupwill be exposed to one of four test conditions (H₂S/17.5 Gy thoracicirradiation, H₂S/no thoracic irradiation, no H₂S/17.5 Gy thoracicirradiation, or no H₂S/no thoracic irradiation), then followed for 13weeks. Twelve animals per group will be similarly exposed and followedfor 26 weeks (the increased n is required to compensate for theincreased mortality that occurs late in the course of the disease).

For these experiments, analysis of variance (ANOVA) will be used as thestatistical model for data analysis. A completely crossed and randomizedtwo factor ANOVA with 4 groups (irradiated or non-irradiated micereceiving H₂S or not receiving H₂S) and two time intervals (13 or 26weeks) will be used to analyze temporal changes in bronchoalveolarlavage inflammatory cell number and total protein concentration and lunghydroxyproline levels. Assuming 80% power, 5% significance and atwo-tailed test, five surviving mice per combination of injury group,intervention group and time point will allow a detectable differenceamong group means greater than or equal to 1.7 times the underlyingwithin-group standard deviation. The within-group standard deviation isexpected to be equal to about 25%. Thus, changes in inflammatory cellnumbers or lung collagen content of 35-50% of control values should bediscernable in these experiments.

H₂S exposure and thoracic irradiation will be done in SLU AHR in alinear accelerator suite. Bronchoalveolar lavage and lung procurement atnecropsy will be performed in the AHR mouse necropsy room.Bronchoalveolar lavage cell counts and protein concentrations and lunghydroxyproline content measurements will be performed in the another lab(D3-255). Wild genotype C57BL/6 mice will receive 17.5 Gy of thoracicirradiation. Mice will be anesthetized with intraperitoneal Avertin,placed into individual cloth mouse restrains and irradiated via thelinear accelerator with 8.5 Gy at a dose rate of 3 Gy/min through twolateral fields collimated to target the thorax only (total thoracic dose17.5 Gy).

B. Protocol

Anesthesia. Wild genotype C57BL/6 mice will be anesthetized forintratracheal dosing with Isoflurane. The depth of anesthesia will bemonitored by respiratory rate for response to tactile stimulation.Intraperitoneal injection of Avertin (0.4-0.7 ml/mouse i.p.) will beused to anesthetize animals for the thoracic irradiation procedure. Thedepth of anesthesia will be monitored by respiratory rate and responseto tactile stimulation.

Exposure to hydrogen sulfide. Mice will be placed into a closedplexiglass gassing chamber similar to the one used previously for mice(IR1606). The chamber will have two ports (import and export). A gascontaining H2S (80 ppm) balanced with room air will be vented throughthe chamber at a rate of 1 liter per minute. The gas will be vented fromthe room using the house ventilation system with a hose that extendsfrom the export vent to the exhaust vent for the room.

Hazardous agent administration. Mice will be irradiated while they arein the gassing chamber with a total dose of 17.5 Gray using the linearaccelerator. This radiation dose will induce an subacute pulmonaryinjury in the mice which progresses to fibrosis. The mice will not beradioactive or otherwise provide a hazard to personnel or other animals.No special monitoring, containment or disposal is required due to theirradiation.

Scheduled euthanasia. At approximately weeks 13 and 26 after thoracicirradiation, the animals will be euthanized by deep anesthesia (usingavertin 0.4-0.7 ml i.p.) followed by exsanguination via inferior venacava puncture. Bronchoalveolar lavage will be performed to determineinflammatory cell number, differential counts and lavage fluid proteinconcentrations. Lung and esophagus tissue will be removed for histologicevaluation and collagen content analysis.

Moribund animals. Thoracic radiation is associated with a finitemortality rate in mice, with 15% dying by week 10 and 50% by week 22post irradiation. The investigators will monitor the animals daily foradverse effects (2-3 times per day initially, until they appear stable,then once daily until disease begins to progress, at which point theinventor will return to multiple daily observations). If an animal islosing weight, failing to groom, exhibiting severe respiratory distress,and/or awkward or significantly diminished movement, it will beeuthanized with an avertin overdose. When practical, bronchoalveolarlavage and tissue collection for histology will be performed for theseunscheduled euthanasias.

Thoracic irradiation should produce a lung injury which itself is notpainful but may manifest itself (week 10) by increased respiratory rate,mild appetite loss, mild weight loss and/or failure to groom. Theinvestigators and animal facility staff will monitor the animals dailyfor such adverse effects. If an animal does not seem to be eating, softfood and fluid support will be provided. If the animal is perceived tobe in pain, analgesia with Butorphanol (0.2 mg/kg i.p.) orBuphrenorphine (1.0 mg/kg bid s.q.) will be administered as needed. Ifan animal appears to be suffering and palliative measures do not lead toimprovement, it will be euthanized immediately. Lung and esophagustissue will be collected for histopathologic evaluation and collagencontent analysis at the scheduled necropsies.

Post-irradiation Husbandry. To minimize the risk of transmitting anypathogens to the rest of the facility, and to protect these animalswhile they are somewhat immunocompromised, all husbandry work on theseanimals will be done first thing each day (before any other animals inthe facility) and will be done in a biosafety cabinet. To minimize therisk of adventitious infections, the mice will have autoclaved cages andbedding. In addition, they will be fed standard rodent food that hasbeen irradiated to kill pathogens.

Wild genotype C57BL/6 mice will receive 17.5 Gy of thoracic irradiation.Mice will be anesthetized with intraperitoneal Avertin, placed intoindividual cloth mouse restraints and moved into a closed plexiglassgassing chamber similar to the one used previously for mice (IR1606).The chamber will have two ports (import and export). A gas containingH₂S (80 ppm) balanced with room air will be vented through the chamberat a rate of 1 liter per minute. The gas will be vented from the roomusing the house ventilation system with a hose that extends from theexport vent to the exhaust vent for the room. Once in the gassingchamber the mice will be irradiated via the linear accelerator with 8.5Gy at a dose rate of 3 Gy/min through two lateral fields collimated totarget the thorax only (total thoracic dose 17.5 Gy). After completionof thoracic irradiation the animals will be returned to theirmicro-isolater cages monitored until recovered from anesthesia.

Scheduled necropsises. One set of animals will be necropsied in week 13post-irradiation to evaluate the inflammatory phase of the injury. Thesecond set will be euthanized in week 26 to evaluate the fibrotic phaseof the injury. Animals will be anesthetized with avertin, thenexsanguinated. The lungs will be lavaged with 1000 μl PBS and the lavagefluid kept on ice for total and differential cell counts. The right lungwill then be harvested for hydroxyproline content and the left lung willbe infused with 10% NBF at 25-30 cm pressure through the trachea. Theesophagus, trachea, left lung and heart will be immersed in 10% NBF andset to the FHCRC histology shared resource lab for processing andpathology evaluation.

Thoracic irradiation should produce a lung injury which itself is notpainful but may manifest itself (week 10) by increased respiratory rate,mild appetite loss, mild weight loss and/or failure to groom. Theinvestigators and animal facility staff will monitor the animals dailyfor such adverse effects. If an animal does not seem to be eating, softfood and fluid support will be provided. If the animal is perceived tobe in pain, analgesia with Batorphanol (0.2 mg/kg i.p.) orBuphrenorphine (1.0 mg/kg bid s.q.) will be administered as needed. Ifan animal appears to be suffering and palliative measures do not lead toimprovement, it will be euthanized immediately by CO₂ asphyxiation.

The primary problems are likely to be esophagitis (resulting indecreased food and water intake) and respiratory insufficiency (reducingoxygen uptake). The inventor will be checking these animals 2-3 timesper day until they are convinced that they are stable and doing well, atwhich point the inventor may reduce the frequency of checks to oncedaily, until the disease begins to progress, at which point they returnto multiple daily checks. Supportive care will be provided in severalways. If an animal is not eating or drinking well (evidenced by weightloss and grooming problems), the inventor will provide soft food and tryfluid supplementation (Lactated Ringer's solution, 1-2 ml/mouse, scusing a small bore needle (>20 G), 1-2 times daily). If the animal isperceived to be in pain, analgesia with Batorphanol (0.2 mg/kg i.p.) orBuphrenorphine (1.0 mg/kg bid s.q.) will be administered as needed. Ifan animal appears to be suffering and palliative measures do not lead toimprovement, it will be euthanized immediately by CO₂ asphyxiation. Inthe event that an animal experiences significant pain or distress at thetime of thoracic irradiation, the animal will be euthanized by CO₂asphyxiation.

A third experiment was to subject a telemetry mouse to a regulatedatmosphere of H₂S at 80 ppm in a reduced cabinet temperature of 10.5° C.essentially as described above. During the experiment, the mouse wasvisually observed and its movements were recorded by web camera, andtelemetry measurements were recorded as described above. The mouse wasexposed to a regulated atmosphere of 80 ppm H₂S, and the temperature ofthe cabinet was reduced to a constant 10.5° C. At the end of anapproximately six-hour period, heat was applied to the cabinet bysetting the cabinet temperature to 25° C. The mouse was allowed to warmup in the regulated H₂S atmosphere until the core temperature of themouse was between 17° C. and 18° C. after which time the regulatedatmosphere was replaced with room air. There was a clear decrease incore body temperature of the mouse to 10.5° C. in the regulatedatmosphere accompanied by a marked drop gross motor movement. Therespiration rate dropped to an undetectable rate by visual observationfor approximately one hour and fifteen minutes. After the cabinet waswarmed, weak respiration was observed when the core body temperature ofthe mouse achieved 14° C. During the warming phase, when the core bodytemperature rose to between 17° C. and 18° C., and the mouse wasexhibiting respiration and movement, the regulated atmosphere wasreplaced with room air. Normal movement and respiration were fullyapparent when the core body temperature returned to 25° C. The mouse hasexhibited no apparent change in the behavior compared to animals thatwere untreated.

Example 6 Cell and Mammal Studies

A. Canine Studies

Canine studies will be conducted with dogs surgically implanted withtelemetry devices to monitor their core body temperature. The animalswill be studied in the presence or absence of a sub-lethal dose ofhydrogen sulfide for 10 hrs. During this time, they will be continuouslymonitored for vital signs by telemetry. The temperature of theenvironment will also be reduced to 15° C. for 30 min to determinewhether this has any effect on the core body temperature of the animals.

The procedure will be conducted with 2 groups of 2 dogs (four total).Because of the expense of the telemetry equipment the inventor will dothese experiments in succession. If the results from the first groupindicate that the hypothesis is incorrect, the study will be repeatedwith the second group of two dogs. If the results from the second groupdo not support the hypothesis, the project will be discontinued.

Toxicology studies demonstrate that, while the level of H₂S is above theOSHA limit for humans (10 ppm), it has been shown previously thatexposure of both rats and mice to 80 ppm of H₂S for 6 hrs per day, 5days per week, for 90 days, showed no observed adverse effect. Thisincluded both gross and histopathological examination of the gut, lung,heart, liver, kidneys, or other organs conducted at the end of thetreatment. To the inventor's knowledge, no information is availableconcerning exposure of dogs to hydrogen sulfide.

A critical issue in working with H₂S is to not exceed the dose (80 ppm)described by others who have published studies on rodents exposed tohydrogen sulfide and not seen detrimental effects. There is considerableexperience in gas sciences available, and the inventor is capable ofdelivering the gas to the mice at the prescribed dose. Many precautionsare taken to ensure that both animals and investigators are not harmed.These precautions include constant monitoring of the gas mixture withalarm set to OSHA limits and sensitivity to 1 ppm, and a variety ofequipment that is able to mix and deliver the gas according tospecifications without leakage into or out of the system.

A time line for the protocol is given in Table 5.

TABLE 5 Study Time Line Day Activity Detail −1 Pre-surgery ACBC/Chemistry will be performed; dog will be fasted in p.m., but allowedfree access to water. 0 Surgery Fentanyl transdermal patch placed p.m.of day before surgery for preemptive analgesia. Preoperative placementof cephalic catheter; premedication with Acepromazine, Buprenorphine,Glycopyrrolate; induction with either Ketamine:Diazepam or Propofol topermit intubation; maintenance anesthesia by isoflurane and oxygen. Dogwill be placed in dorsal recumbancy and the abdomen clipped/prepped anddraped. Monitoring of pulse, respiration rates, end-tidal carbonedioxide, inhaled percentage of anesthetic agent, SpO₂ will be performedand recorded every 15 minutes or more frequently. Fluid support duringand after surgery will occur. Once the dog is stable and appropriatelyprepared for the procedure, a ventral midline laparotomy, beginningcaudal to the umbilicus and extending 5-10 cm caudally, will beperformed. A sterile transmitter will be placed into the peritonealcavity. Placement will be checked to insure that the transmitter is ableto move freely; the momentum will be replaced, and closure of theperitoneal cavity will be performed in 3 layers. The dog will bemonitored until it is extubated, is able to thermoregulate and issternally recumbent. Daily monitoring of the dog's incision site,abdomen (via palpation and ultrasound, if indicated), appetite,temperature (for the first 3-5 post-operative days), weight and activitywill be performed. 7 Establishment This date is flexible. Will onlyproceed with this step with of Baselines approval. Four animals will beplaced onto the receiver equipment (this does not involve removal of theanimals from their cages and will occur in AHR) and baselines for thevital signs will be established for all four animals. 8 Exposure toAnimals will be transferred to a room to be determined where H₂S theywill be placed into caging with food and water that has an enclosedatmosphere. After establishing baselines two of the four animals will besubjected to H₂S at a concentration of 80 ppm. Following a ten-hourexposure, the atmosphere will be returned to room air temperature andthe animals will be returned to their cages. Exposure to H₂S willrepeated once per week to begin to determine whether any data set isreproducible.

B. Human Platelets

To test the concept that using inhibitors of oxidative phosphorylationcould be used for human benefit, the inventor induced a state ofsuspended animation in human tissues to protect them from lethalexposure to oxygen. In pilot experiments, the inventor placed human skinin an environment of 100% CO. The inventor observes that after 24 hrsskin cells survive 100-fold better in CO than those in room air. Theseresults are very exciting; they provide evidence that inhibitors ofoxidative phosphorylation can be effective in human tissues.

Another set of experiments demonstrates the protective effects ofinduced suspended animation on platelets. A unit of platelets was splitin half. The first half was kept at standard storage conditions, whichinvolves keeping the platelets at room temperature (22-25° C.) withconstant shaking. The other half was placed inside an anoxic environment(<10 ppm oxygen) using standard methods to remove the oxygen. The twosets of platelets were compared on days 0, 5 and 8. The platelets keptin anoxic conditions performed as well or better than those kept atstandard conditions over a panel of five different in vitro tests,including the ability to aggregate, cell morphology, Annexin-V staining(phosphatidyl-serine flipping to the outer membrane as an earlyapoptotic marker), and so on. This indicates that controlling metabolicactivity, specifically oxidative phosphorylation, can be accomplished bythe removal of oxygen and has a protective effect on cellular functionover long periods of stasis.

Hydrogen sulfide is able to bind cytochrome C oxidase as well as CO andstop oxidative phosphorylation on demand. It is so potent at impedingoxidative phosphorylation, that should a person take a single breath inan atmosphere with 0.1% hydrogen sulfide, they will not take another.Instead, they immediately collapse to the floor—an event commonlyreferred to in industrial settings as a “knock down.” It also appears tobe reversible because, if rapidly removed to fresh air (and uninjuredfrom the fall) these individuals can sometimes reanimate and go on tolive without neurological problems. Here is an agent that is not onlycommon in our world, indeed, is produced even in our own cells, but isalso a potent reversible inhibitor of oxidative phosphorylation thatdoes not effect oxygen delivery.

C. Murine Studies

Induction of a Hibernation-Like State Using H₂S. Homeothermic animals,by definition, maintain a core body temperature 10-30° C. above theambient temperature. For these animals to do this, they must generateheat from the energy produced by oxidative phosphorylation. The terminalenzyme complex in oxidative phosphorylation is cytochrome c oxidase.Since hydrogen sulfide inhibits this complex (Petersen, 1977; Khan etal., 1990), the inventor predicts that exposing a homeothermic animal tohydrogen sulfide will prevent such an animal from maintaining its corebody temperature well above ambient temperatures.

To test this hypothesis, the inventor wanted to continuously monitorboth the core body temperature and the activity levels of a homeothermicanimal (a mouse). Telemetry devices, implanted into the peritonea ofmice, can do both of these things and have the advantage of notintroducing bias to the readings due to the handling of the mice(Briese, 1998). Additionally, they can remotely monitor the mice duringthe exposure to the hydrogen sulfide gas. A dose of 80 parts per million(ppm) hydrogen sulfide has been previously shown to be innocuous to micefor exposures lasting up to ten weeks (CIIT 1983; Hays, 1972).Therefore, for these experiments the inventor used a dose of 80 ppmhydrogen sulfide to test our hypothesis. Creating an atmospherecontaining 80 ppm of hydrogen sulfide is not trivial. Over time, in thepresence of oxygen, hydrogen sulfide will be oxidized to sulfate. Forthat reason, in order for the inventor to continuously expose a mouse toan atmosphere containing 80 ppm hydrogen sulfide, the inventorconstantly mixes room air with a tank of 500 ppm hydrogen sulfidebalanced nitrogen.

Characterization of Core Temperature Control

Exposing a mouse to 80 ppm H₂S dropped its core temperature toapproximately two degrees Celsius above ambient (FIG. 5). This effectwas highly reproducible as the average core body temperature of sevenmice exposed to 80 ppm of hydrogen sulfide for 6 hrs followed a similarpattern (FIG. 5). The lowest average core body temperature of theseseven mice was 15° C. in an ambient temperature of 13° C. All of thesemice successfully recovered after rewarming when the atmosphere wasswitched to one containing only room air. As a control, the inventorsubstituted nitrogen for the hydrogen sulfide and did not see thesubstantial drop in core body temperature.

Although these mice appear superficially normal despite temporarydecrease in both core body temperature and breathing rate, the inventorconducted a battery of behavior tests to rule out the possibility thatneurological damage was incurred by either the exposure to hydrogensulfide gas, the extreme reduction in core body temperature, thereduction in breathing rate, or the combination of these effects. All ofthe tests were performed on the mice both before and after exposure tohydrogen sulfide. These behavior tests were selected from the SHIRPAprotocol developed by the Mouse Models for Human Disease consortium(Rogers et al., 1997). There were no detectable behavioral differencesin the mice after gas exposure. From this, the inventor concluded thatentry into a hibernation-like state is not detrimental.

Preliminary Optimization of H₂S Dose. The above experiments describe theeffect of 80 ppm of hydrogen sulfide on the core body temperature of amouse. In order to determine the concentration of hydrogen sulfidesufficient for the loss of thermoregulation, the inventor exposed miceto a range of hydrogen sulfide concentrations (20 ppm, 40 ppm, 60 ppm,and 80 ppm), (FIG. 6). While 20 ppm and 40 ppm of hydrogen sulfide weresufficient to cause a drop in the core body temperature of a mouse, thiswas minor compared to the drop seen with 60 ppm and 80 ppm of hydrogensulfide. From this experiment, the inventor concluded that the loss ofthermogenesis is directly dependent upon the concentration of hydrogensulfide given to the mice. This preliminary study on the dose range andpharmacokinetics of hydrogen sulfide emphasizes the need for a morecomprehensive analysis.

Preliminary Definition of Low Core Temperature Limit. The inventor isalso interested in establishing a more complete understanding of thetolerance of both the range of core body temperatures and the length oftime allowed in this state for mice. The experiments above show that theinventor can repeatedly lower the core body temperature of a mouse to13-15° C. on demand. Furthermore, the mice seem to tolerate thetreatment for many hours. Using the same protocol, while lowering theambient temperature, the inventor has successfully brought the core bodytemperature of a mouse to 10.7° C. (FIG. 7). Further attempts to pushcore body temperatures even lower, and for longer periods of time, willbe performed in the future. Although preliminary, these resultsdemonstrate that there is a significant range of core body temperaturesallowed by mouse biology and that this range can be explored through theloss of thermoregulation due to hydrogen sulfide exposure.

Modulation of Endogenous H₂S Levels. It is well known that mammaliancells make hydrogen sulfide endogenously (Wang 2002). Since thischemical is dynamically produced in the cell, it is crucial tounderstand the basal levels under different conditions as this coulddramatically affect the pharmacokinetics of exogenously administeredhydrogen sulfide. To address this essential aspect of our research, theinventor has begun to assay endogenous hydrogen sulfide levels in themouse. The inventor uses an extractive alkylation technique coupled withgas chromatography and mass specific detection to quantify hydrogensulfide (Hyspler et al., 2002). Using this method, the inventor lookedat the levels of hydrogen sulfide in unperturbed mice. FIG. 8A showsthat there is a significant amount of hydrogen sulfide within the mouse.Additionally, the levels of hydrogen sulfide appear to be dependent uponthe ambient temperature of the mouse. Specifically, when mice are in thecold, they have reduced endogenous sulfide levels and, when mice are atwarm ambient temperatures, they have increased endogenous sulfidelevels. From this, the inventor concludes that mice regulate theirsulfide levels in response to the ambient temperature.

Changes in Endogenous Levels Affect the Efficacy of H₂S. Since theambient temperature changes the endogenous levels of sulfide in mice,the inventors hypothesized that the ambient temperature might impact thechanges in core body temperature upon exposure to exogenous hydrogensulfide. Acclimatizing a mouse to cold temperatures, 12° C., creates alonglasting plateau that the inventor sees after the initial drop incore body temperature (FIG. 8B). Therefore it appears that thisacclimatization to the cold made the mouse more resistant to core bodycooling by the action of hydrogen sulfide gas. However, allowing themouse to acclimatize to a warm thermoneutral temperature prior to gasexposure eliminates this plateau. In fact, the normothermic mouse cooledmuch more quickly when exposed to hydrogen sulfide than thecold-acclimated mouse (FIG. 8B). These data suggest that endogenouslevels of hydrogen sulfide in the mouse have a direct impact upon theefficacy of the exogenous hydrogen sulfide.

H₂S protects mice from hypoxia. Normal room air contains approximately21% oxygen. In a preliminary experiment exploring the protective effectsof stasis on hypoxia in the mouse model, a mouse exposed to 80 ppm ofhydrogen sulfide survived 11 minutes of 5.2% oxygen and 3 weeks later,it was still doing well. Previously published work shows that 90% ofthese animals (C57B1) exposed in this way without hydrogen sulfide donot survive (Zhang et al., 2004). This experiment involvedpre-equilibrating the mouse to 80 ppm H₂S for 3 hours, then dropping theoxygen tension in the chamber as described in experiments above. Thesame flow rates were used as described above (i.e., 500 cc/mL in a 0.5 Lchamber). It is well established in those familiar with the field thatif a group of mice are exposed to 4% oxygen, 100% will be dead within 15minutes. However, mice in which H₂S is administered during periods whenthe oxygen tension is reduced to 4%, remain viable, even for extendedperiods (up to an hour) in these hypoxic conditions. The mice appear tobe unaffected by these conditions after recovery, and are viable andnormally responsive when tested 24 hours later. This experiment differsfrom the one above in that the mice were retained in the H₂S at the endof the hypoxic exposure until the oxygen tensions were returned tonormal levels (21% O₂).

Example 7 Additional Animal Studies

A. Protection from Adverse Conditions

Experiments were conducted to test the ability of a mouse in a‘hibemation-like’ state to survive in conditions where it would normallydie. The adverse condition was hypoxia, which the literature states thatmice (C57BL6/J males) can live in for a maximum of 20 minutes at 5%Oxygen. (Zhang et al. 2004).

As shown in Table 6, the experiment involved exposing the mouse to 80ppm (unless otherwise noted) H₂S for the time indicated, followed by thedecrease in oxygen tension in the chamber, while still under H₂S. Thehypoxic exposure was timed (indicated below) and viability of the micewas determined.

Short exposures of the mice to H₂S (at least at 80 ppm) was lesssuccessful at protecting the mouse from hypoxia, although there was atleast one that did survive a 50-minute hypoxic exposure after just 8minutes in H₂S. Furthermore, it was observed that a mouse exposed to 90ppm H₂S for just 10 minutes did survive much longer in the 5% Oxygencondition, although it did eventually expire.

Exposing the mice to 80 ppm H₂S for longer periods of time had a strongeffect on protecting them from hypoxia for up to an hour.

TABLE 6 Time in H2S Ambient Prior to hypoxic Time in Temp exposureOxygen % Hypoxia Result 20° C.   5 hrs 5.20% 11 minutes life 20° C. 5.5hrs 5.00% 25 minutes life 20° C.   5 hrs 5.00% 60 minutes life 20° C.  5 hrs   4% 28 minutes life 24° C. no H2S   5% 14 minutes dead 24° C.simultaneous 5.10% 10 minutes dead 24° C.   8 minutes   5% 20 minutesdead 24° C.   8 minutes 4.00%  8 minutes dead 24° C.   8 minutes 4.50%23 minutes dead 30° C.   8 minutes 4.50%  6 minutes dead 24° C.  10minutes   5% 56 minutes dead (90 ppm) 24° C.   8 minutes 5.00% 50minutes life

B. Enhancing Anoxia Tolerance

1. Background

The use of carbon dioxide (CO₂) and hydrogen sulfide (H₂S) to enhancethe survival of a complex metazoan, Drosophila melanogaster, in anoxiawas investigated. These experiments indicated that these agents,especially H₂S, can increase the anoxia tolerance of adult D.melanogaster.

C. elegans embryos survive in anoxia (<10 ppm O₂) by entering intosuspended animation, and development can proceed in 0.5% O₂. However,there is a 10-fold range (0.01-0.1% O₂) of lethal oxygen concentrations.Moreover, preventing oxygen utilization with carbon monoxide can preventhypoxic damage in embryos. Thus, if there is not enough oxygen availablefor efficient biological activity, then it is better to not have (oruse) any oxygen.

In more complex metazoans, the cellular oxygen concentration is notnecessarily the same as the environmental oxygen levels. In C. elegans,oxygen is delivered to the tissue by diffusion. However, in higherorganisms there are proteins that bind oxygen in order to transport itto the tissues, such as hemoglobin. Therefore, when environmental oxygenlevels drop, there may be residual oxygen at the cells.

Most organisms are not able to survive exposure to environmental anoxia.One possibility is that the residual oxygen at the cellular level istoxic, corresponding to the lethal oxygen range observed in C. elegansembryos. In this scenario, survival of anoxia would be enhanced if theresidual oxygen was removed or made un-utilizable. CO₂ promotes therelease of O₂ from hemoglobin and H₂S is a potent inhibitor of oxidativephosphorylation.

2. Materials and Methods

Basic experimental setup. Adult flies were introduced into 35 mL tubesmade of glass with a gas-tight rubber stopper (Balsh tubes). This wasusually accomplished by anesthetizing flies with CO₂, moving groups offlies to vials with food to recover for at least 2 hours, and thentransferring them into the Balsh tube. To exchange the gaseousenvironment in the Balsh tube, two 18 gauge needles were inserted intothe rubber stopper, and gas is blown into one of the needles at 100mL/min. To prevent dessication, gasses were humidified by bubblingthrough 10 mL of water before passing it through the Balsch tube. Thewater in the bubbler is equilibrated with the gas for at least 20minutes before starting the experiment.

For “stopped-flow” experiments, gas exchange proceeded for 60 minutesbefore sealing the tube. For “low-flow” experiments, gas flow continuedthroughout the experiment. CO₂ was from the house source (100%), andanoxic environments were established by flushing out room air with 100%nitrogen (N₂). Care was taken to prevent introduction of room air intothe system while switching the atmosphere from CO₂ to N₂.

After anoxic treatment, oxygen was reintroduced into the Balsh tube byflushing with house air for 20 minutes. The rubber stopper was thenremoved and a food vial is inverted over the top of the Balsh tubes withParafilm. Flies were scored as alive if they resume movement. Viabilitywas scored at least 18 hours after the end of anoxic treatment. Aftertwo weeks, if the food vials contained larvae and/or pupae the flieswere considered to be fertile.

3. Results

Treatment with CO₂ prior to anoxic exposure. Adult flies exhibited ahigher rate of anoxic survival if they are first pretreated with CO₂.After a 19 h anoxic exposure in a stopped-flow experiment, adult fliespretreated with CO₂ for 30 or 90 minutes exhibited 54% or 28% survival,respectively. No survival was observed in controls exposed to anoxiawithout CO₂ pretreatment or CO₂ without subsequent anoxic exposure.Furthermore, no flies survived anoxic exposure with CO₂ pretreatment ifthey were also exposed to CO₂ immediately following anoxic exposure for20 minutes.

A short exposure to CO₂ was sufficient for enhanced survival of anoxia.In stopped-flow experiments with 22 h anoxic exposure, the fraction offlies that survive was highest if CO₂ was administered for 0.5-5 minutesbefore switching to the nitrogen atmosphere (FIG. 16). Thus, forsubsequent experiments, the standard protocol was to treat with CO₂ for10 minutes before anoxic exposure. In a low-flow experiment using thisprotocol, 6% of adult flies survived a 20 h anoxic exposure, and thissurvival required the CO₂ pretreatment.

Experiments suggested that it is important to prevent reintroduction ofO₂ between the CO₂ treatment and establishing the N₂ environment. Whenthe water in the bubbler used to humidify the air was not equilibratedwith N₂ before flushing out the CO₂, no flies survived a 13 h anoxicexposure in these experiments, whether the N₂ was introduced at 10, 50,or 100 mL/min. Under these conditions, the CO₂ atmosphere was flushedout with a N₂/O₂ mix resulting from the O₂ dissolved in the water.

A series of low-flow experiments were conducted to determine the time ofanoxic exposure that can be tolerated with CO₂ exposure compared to nopretreatment, testing each condition in duplicate (FIG. 17). In thesedata, the trend is that CO₂ pretreatment results in greater survival. Animportant caveat is that these experiments deviated from the standardprotocol in that the flies were anesthetized with CO₂ and transferred tothe Balsh tubes and allowed to recover for only 10-20 minutes beforeinitiating the CO₂ treatment (except for Trial 2 of the 18 h timepoint).

Several other experiments were performed that were not informative towhether pretreatment with CO₂ was beneficial. For instance, in oneexperiment no survival was observed after 17, 22, and 24 h of anoxia ina low-flow experiment with a 10 min CO₂ pretreatment period. However, inother experiments, many flies survived after 17 h. This may indicatethat in certain cases other factors affect the outcome, such as age ofthe adults, circadian rhythms or variations in room temperature. Inanother experiment to compare the stopped-flow setup to the low-flowsetup, no flies survived a 17 or 19.5 h anoxic exposure; however, inthis instance mold contamination may have contributed to the demise ofthe flies.

Treatment with H₂S prior to anoxic exposure. Including H₂S in thepretreatment protocol more dramatically enhanced the ability of adultflies to survive anoxia. In a series of experiments analogous to thoseshown in FIG. 17, adding 50 ppm H₂S to the CO₂ pretreatment (H₂S/CO₂)increased the fraction of flies that survived treatment (FIG. 18). Theseflies seem healthy, and produced progeny after exposure. However, in asimilar experiment no flies survived 18, 20, 25, or 30 h in anoxia after10 minutes in H₂S/CO₂. The cause of this discrepancy is unclear.Consistent with a beneficial influence of H₂S treatment, after a 15 hanoxic exposure 50% of flies pretreated with H₂S survived, whereas therewas no recovery of control flies that were not exposed to H₂S. In thisexperiment, the flies were treated with CO₂ for 10 min, then H₂S/CO₂ for10 min, then N₂/H₂S for 10 min, and finally with N₂ for the duration ofthe low-flow experiment.

CO₂ treatment is not required for the H₂S-dependent increase in survivalof anoxia. 25% of flies treated with 50 ppm H₂S in room air prior tobeing made anoxic for 18.5 h survived. The fraction of flies survivingwas unaffected if a 10 min exposure to H₂S/CO₂ was added beforeestablishing the anoxic environment. In a control experiment where flieswere treated only with CO for 10 min before the anoxic exposure, only11% of the flies recovered.

The time at which H₂S is administered appears important for enhancinganoxic survival. If H₂S is present throughout the anoxic exposure (20 h)no flies recover, whether H₂S was present during the CO₂ pretreatment ornot. However, 35% of flies survive if 50 ppm H₂S is present in the CO₂pretreatment and then is removed as the anoxic environment isestablished. In parallel experiments, 6% of flies exposed to anoxiaafter 10 min pretreatment with CO₂ (no H₂S) survived.

Preliminary experiments with larvae and embryos. The enhanced survivalof anoxia after treatment with CO and CO with HS is also observed inembryos and larvae. After exposure to anoxia for 24 h, 7 pupae werefunned from a pool of 0-19 h old embryos. However, 20 pupae wereobserved from a matched pool that was pretreated with CO₂ for 10 min.Similarly, larvae exposed to 24.5 h anoxia can resume movement uponreoxygenation only if they were pretreated with CO₂ or H₂S/CO₂. 0-24 hold embryos survive 18.5 h anoxic exposure and develop to adulthoodwhether pretreated with CO₂ or H₂S/CO₂.

Cold treatment during anoxia. Decreasing the environmental temperaturemay extend the length of time that adult flies can survive anoxicexposure. At room temperature, no flies survived a 15.5 h anoxicexposure in a stopped-flow setup, but 20% of those kept at 4° C. whileanoxic recovered. Similarly, no flies survived being transitioned toanoxia at 4° C. and then moved to room temperature for 16.5 h. However,after 16.5 and even 40 h flies that were kept at 4° C. during the entireexposure recovered and were fertile. Pretreating with CO₂ beforeestablishing anoxic environment did not have a noticeable difference inthese experiments.

Example 8 Drop in Core Body Temperature

In both rats and mice, it was shown that using H₂S and CO₂, metabolicoutput can be reduced, shown as reduced body core temperature. FIG.20A-B show that at time 0 when H₂S or CO₂ are first applied, the bodycore temperature of the animals begins to drop. Six hours later, whenthe H₂S or CO₂ are removed, the temperature begins to return to normal.It is clear that larger mammals require more H₂S to affect metabolism.

Prophetic Example 9 Gas Matrix

In order to determine the concentration of each component gas in acustom mixed atmosphere that provides the greatest capacity to controlmetabolic flexibility in mammals, the following experiments can beperformed. The gases include oxygen (O₂), nitrogen (N₂), carbon dioxide(CO₂), hydrogen sulfide (H₂S), and helium (He). While H₂S probablyreduces oxygen demand in mitochondria, CO₂ may further reduced oxygendemand. In addition, it has been found that reduced body coretemperature is essential for reduced metabolism. Therefore, helium gas,with its high heat capacity, may provide a simple and noninvasivecooling method. Furthermore, using 100% O₂, a normoxic 20.95% oxygen canbe maintained in any gas mix in which the other constituents make upless than 79.05% of the total. And finally, nitrogen is used to balancethe mix to 100%.

These experiments describe a progressive approach to assay the gasessingly and in combination first in mouse then rat, then dog. It is thegoal with this gas matrix to develop a foundation on which to work withmultiple variables in a logical order. The experimental design isdepicted in FIG. 21.

One of the features of the gas matrix is that it makes clear thatexperiments will only be performed if previous experiments (linked byarrows) are complete. Mixing experiments will not be performed in anyanimal model without first optimizing the component gases. Furthermore,a gas or gas mix will not be used in a rat without first optimizing thedose in mouse nor in a dog without first optimizing in rat. Thus, itshows the progression of experiments using single gases to multiple gasmixes (reading top-right to bottom-left) and mice to rats to dogs(reading top-left to bottom-right). Mice will always be used first todetermine the concentration of component gases that provide the bestcontrol of metabolic flexibility. Once the most effective dose of a gasis determined using mice, the same experiments will be performed in rat.At the same time, the next gas or gas mix will be assayed using mice.Once the concentration is determined in rat, the gas will be tested indogs. The following table provides a slightly different way to view thegas matrix and defines the order of experiments:

sequential order mouse rat dog 1 H₂S + CO₂ CO₂ 2 He/O2 H₂S + CO₂ CO₂ 3H₂S + CO₂ + He He/O2 H₂S + CO₂ 4 H₂S + CO₂ + He He/O2 5 H₂S + CO₂ + HeProcedure 1. Carbon dioxide (CO₂)

Mice: It was found that 15% CO₂ affords control of metabolic flexibilityin mice. However, given the limitations of our mixing abilities, we wereunable to test higher concentrations. This is no longer true, and we cantest CO₂ concentrations up to 80%. Therefore, we will begin at 15% CO₂and increase in 5% increments to 40% then 10% increments to 80%. Animalswill be exposed for 6 hours. Mice will be exposed using a 375 ml glasschamber in which the animals will be supplied with water and into whicha premixed gas atmosphere will be flowed at a rate of 500 milliliter perminute. These chambers will be contained in an incubator so that ambienttemperature can be controlled. This table provides a framework for ourhigh-concentration CO₂ experiments but additional experiments may berequired to better understand the effects. Mice can be used in multipleexperiments but we will not use an animal more frequently than once perweek. Furthermore, animals can function as their own controls insubsequent experiments.

% CO₂ 15 20 25 30 35 40 50 60 70 79 % O₂ 21 21 21 21 21 21 21 21 21 21 %N2 64 59 54 49 44 39 29 19 9 0

Metabolism (O₂ consumption and body core temperature) and activity willbe monitored. At 15% CO₂, tidal volume increases but respiration rateremains unchanged. The mice do not appear to “gasp”. Increasing CO₂concentrations should increase the narcotic effect.

These experiments will be performed in an incubator so that we can thenreduce ambient temperature to 10° C. to assay the relationship betweenbody core temperature and metabolic output.

Rats: Experiments in rats will begin using a 3% CO₂ and 21% O₂ balancednitrogen environment. This is regarded as normocapnia as it is theexhaled concentration of CO₂. From 3% we will increase in 2% incrementsto 15%. This increase can be performed in a single baseline experimentwhere we increase the CO₂ concentration until we see a change inmetabolism. Metabolism will be monitored by measuring O₂ consumption andbody core temperature. A single rat in one experiment can be used todetermine this minimal CO₂ dose. In subsequent experiments, where theeffects of 6 hours of CO₂ exposure will be assayed, a single rat will beused for a single CO₂ dose (i.e., the level will not change during theexperiment). Rats can be used in multiple experiments; they will be usedno more than one time in a week. Rats will be exposed using a 2800 mlglass container in which the animals will be supplied with water andinto which premixed gases will be flowed at a rate of 3 liters perminute. This table shows the structure of the first CO₂ experimentsusing rats but others may be required to fully explore the effects.

% CO2 3 5 7 9 11 13 15 % O₂ 21 21 21 21 21 21 21 % N₂ 76 74 72 70 68 6664

From 15% to 80% experiments will progress as was done using mice (5%increments from 15%-40%, 10% increments from 40%-80%). Metabolism andbehavior will be monitored. Once the effective dose of CO₂ for the ratsis determined, the ambient temperature will be reduced to learn ifmetabolism is further reduced by reduced body core temperature as it isusing H₂S. These experiments will be performed in an incubator that willprovide the cooling at the beginning of and during the experiment aswell as the heat at the end of the experiment.

After completion of the rat CO₂ studies, it will be known if ratsrequire more CO₂ than mice to reduce their metabolism (as is true forH₂S), the same, or less. Understanding of this key allometric trend willprovide a better hypothesis for the active CO₂ dose in dogs.

The stopping points for these procedures in mice and rats will be a dropin O₂ consumption by 99% or a drop in CO₂ production by 99%.

Dogs: The experimental design for the dogs will be the same as that usedfor rats and mice (using a flow rate of 10 liters/minute). Experimentswill begin using 3% CO₂ and increase until a physiological response isseen. Dogs will be exposed to mixed gases using an anesthesia mask towhich they have been preconditioned before exposure. O₂ consumption andbody core temperature will be monitored. The same one or two dogs can beused for these experiments.

Procedure 2. Hydrogen sulfide and Carbon dioxide (H₂S+CO₂)

By mixing H₂S and CO₂ we will look for synergistic effects of the twogases. That is, can H₂S and CO₂ be used together to reduce metabolism asprofoundly as higher concentrations of single gases. In the firstexperiments, using mice, H₂S at 20 ppm and titrated in CO₂ to 15% (orother concentration to be determined in procedure 1) will be used. Asingle animal can be used to vary the concentration of CO₂ while holdingH₂S constant. Second, we will use 40 ppm H₂S and add CO₂ to 15%. Third,we will use 80 ppm H₂S and bring CO₂ to 15%. A single animal can be usedin each of these experiments. O₂ consumption, body core temperature, andbehavior will be monitored. The experiments listed in the table(s)provide a foundation for exploring the effects of the H₂S+CO₂ mix andother experiments will be necessary to understand effects.

exp O₂ % H₂S ppm CO₂ % 1 21 20 5-10-15 2 21 40 5-10-15 3 21 80 5-10-15

Once an effective mix is determined, ambient temperature will be loweredto learn if the optimized gas mix synergizes with lower body coretemperature to further lower metabolic rate. In these temperaturedependent experiments, the concentrations of the gases in the mix willnot change. Once again, one animal can be used in multiple experimentswith no more than one experimental procedure per animal per week.

The experiments using rats and dogs will be performed using the samemethodology. The CO₂ concentrations for rat and dog will be optimized inprocedure 1 but it is hypothesized that they will be between 5% and 15%.For dogs, the high H₂S concentration is greater than 400 ppm but has notyet been determined.

Procedure 3 Helium (He)

Helium is an effective heat dissipator; its thermal conductance is sixtimes greater than nitrogen. It has been used in many mammals includingrats, dogs, and humans to promote cooling. It is non toxic, inexpensive,and easy to handle. It is desirable to use helium as others have in an80%/20% mixture with oxygen (He—O₂) to enhance thermal conductivity viarespiration. Five preliminary experiments are proposed to analyze theeffect of He—O₂ on metabolism and behavior. The standard 80%-20% mixthat is widely used will be employed. A mix containing 60% He will alsobe tested to better reflect the minimum He—O₂ mix we will use inprotocol 5 where we mix H₂S, CO₂ and He.

exp. animal temp He—O₂—N2 1 mouse 23° C. 80-20-0 2 mouse 10° C. 80-20-03 mouse 23° C.  60-20-20 4 mouse 10° C.  60-20-20 5 rat 23° C. 80-20-0 6rat 10° C. 80-20-0 7 rat 23° C.  60-20-20 8 rat 10° C.  60-20-20 9 dog23° C. 80-20-0 10 dog 23° C.  60-20-20

Oxygen consumption, carbon dioxide production, body core temperature,and behavior will be monitored to learn if the same effects that othershave using He—O₂ can be induced.

Procedure 4: Oxygen (O₂)

That reduced oxygen concentration can reduce body core temperature wasshown by Gellhorn and Janus in 1936 using Guinea pigs. It is desired toreproduce these experiments first in mice, then in rats, and finally indogs to learn if decreased O₂ concentration decreases metabolism.

Mice: Experiments are proposed in which mice will be exposed todecreasing concentrations of O₂ down to 6%. Experiments will progress in5% increments. O₂ consumption, CO₂ production, body core temperature,and behavior will be assayed. If convulsive behavior indicative ofextreme hypoxia is observed, O₂ will be returned to 21%. The table belowprovides a general outline of the O₂ experiments. Exposure time is sixhours in a controlled chamber (with water) into which premixed gas isflowed. Since there is evidence of hypoxic preconditioning, fourseparate animals for these four experiments.

exp. % O2 % N2 1 21 79 2 16 84 3 11 89 4 6 94

Once the relationship between O₂ tension and metabolism has beendetermined, it may be important to repeat the experiments in a coldenvironment. These experiments will be performed exactly as the previousexperiments except the temperature of the incubator will be lowered to10° C.

Rats: It is desirable to conduct the same experiments using rats thatwere performed previously with mice. If convulsive behavior indicativeof extreme hypoxia is observed, O₂ concentration will be returned to21%.

Dogs: If a positive correlation between reduced oxygen tension andreduced metabolic rate is observed in mice and/or rats, it will bedesirable to perform the same series of experiments using dogs.

Procedure 5: Hydrogen sulfide, Carbon dioxide, Helium, and Oxygen(H₂S+CO₂+He+O₂)

These experiments are the goal of the gas matrix; to determine mix ofO₂, CO₂, H₂S, and He combined with optimized ambient temperature thataffords the most robust and reversible control of metabolism. Therefore,using the concentrations of the individual gases that were determined inthe previous procedures as a foundation, mixes of the four gases will beassayed to find the one which affords the best control of metabolicflexibility. O₂, CO₂, and H₂S will be varied relative to one anotherwhile helium will be used to balance the mix. In the mouse experimentsshown below, CO₂ will be varied while O₂ and H₂S will be held constant;helium will be changed to maintain constant flow. We will use the samemetabolic assays including oxygen consumption and body core temperature.A single animal can be used in multiple experiments. Mice will beexposed for six hours. These experiments will then be repeated usinglower ambient temperature to learn how much reduced body coretemperature affects metabolism using the gas mix.

Mouse: O₂ H₂S CO₂ He exp. conc. % conc. ppm conc. % balance 1 21 205-10-15 2 21 40 5-10-15 3 21 80 5-10-15 4 16 20 5-10-15 5 16 40 5-10-156 16 80 5-10-15 7 11 20 5-10-15 8 11 40 5-10-15 9 11 80 5-10-15 10 9 205-10-15 11 9 40 5-10-15 12 9 80 5-10-15 13 6 20 5-10-15 14 6 40 5-10-1515 6 80 5-10-15

Rats: After it is learned what the optimal gas mixture is for mice,experiments using rats will bedone identical to those performed usingmice except the H₂S concentrations are 100, 200, and 300 ppm. Rats willbe treated for 6 hours.

Dogs: Experiments using dogs will be identical to those using mice andrats. The concentrations will begin at 300 ppm and go to ato-be-determined concentration. Single animal can be used for multipleexperiments but not more than once per week. Mice and rats will betreated for 6 hours, dogs will be treated for two hours.

Prophetic Example 10 Hydrogen Sulfide Dose Selection in Humans

Hydrogen sulfide can be administered to an animal or human to inducestasis by any of a number of dosage forms and routes of administration,including, but not limited to, inhalation of the gaseous form orintravenous administration of a solution of hydrogen sulfide. A methodto determine the dosage form and route of administration of hydrogensulfide sufficient to induce stasis in a whole organism in need ofstasis is described. A test organism (e.g., a rat, dog, pig, monkey) isexposed to increasing concentrations of hydrogen sulfide administeredeither as bolus doses, intermittently, or continuously, and thephysiological state, including but not limited to, core bodytemperature, oxygen consumption, carbon dioxide production, heart rate,blood pressure, breathing rate, blood pH, movement, and wakefulness aremonitored while at various timepoints blood samples (0.5 mL) areremoved. Concentrations of hydrogen sulfide that are present in the testanimals' blood-derived plasma are measured using methods known in theart, including, but not limited to X derivatization, Y extraction, andquantitation using gas chromatography and mass spectrometry.

Correlation of the steady state plasma levels of hydrogen sulfideengendered by a particular dosing regimen in the test animal with theachievement of stasis, to varying degrees, in the test animal, definesan effective dose of hydrogen sulfide sufficient to induce stasis in thetest animal. The effective dose for inducing stasis in a human in needof stasis is determined by identifying the dose, route ofadministration, and dosing regimen of hydrogen sulfide that achieves thesame steady state plasma concentrations of hydrogen sulfide in thehumans as are achieved in the test animals under conditions where stasisis induced. The effective concentration of hydrogen sulfide to achievestasis in a human depends on the dosage form and route ofadministration. For inhalation, in some embodiments effectiveconcentrations are in the range of 50 ppm to 500 ppm, deliveredcontinuously. For intravenous administration, in some embodimentseffective concentrations are in the range of 0.5 to 50 milligrams perkilogram of body weight delivered continuously.

The range in each case is characterized by increasing degrees of stasisachieved with increasing dose of the hydrogen sulfide. A dose ofhydrogen sulfide sufficient to cause a sustained, 12-24 hour drop ofthree to five degrees Celsius to 32-34 degrees Celsius in the core bodytemperature of a human who has suffered out-of-hospital cardiac arrestand who is unconscious upon resuscitation and resumption of a heartbeatis predicted to have a significant survival advantage over a similarhuman not exposed to hydrogen sulfide, as described in Bernard et al.2002.

Example 11 Animal Pre-Treatment Studies

The studies shown in Example 7 demonstrated that prior and continuoustreatment of male C57B1/6 mice with H₂S can enhance their ability tosurvive under hypoxic conditions of 5% oxygen or 4% oxygen.

To determine the effect of H₂S pre-treatment alone on survivabilityunder hypoxic conditions (without continuous H₂S exposure duringhypoxia), mice were exposed to either 30 minutes of room air (No PT) or10 minutes of room air followed by 20 minutes of 150 ppm H₂S in room air(PT) before exposure to 5% O₂ (5%), 4% O₂ (4%), 1 hr 5% O₂ followed by4% O₂ (4%+1 hr 5%), or 1 hr 5% O₂ followed by 3% O₂ (3%+1 hr 5%), andtheir survival time determined. Experiments were stopped at 60 minutes,and animals still alive were returned to their cage. As shown in FIG.23, all of the mice in a cohort of animals pre-exposed to 150 ppm H₂S inroom air for 20 minutes survived subsequent exposure to 5% O₂, while allof the control animals exposed to room air alone had died within 15minutes of exposure to 5% O₂. Thus, pre-exposure of mice to H₂Sestablishes a physiological state in the mice that allows prolongedsurvival to otherwise lethal hypoxia. The protection observed in H₂Spre-treated mice far exceeds the known protective effect of whole bodyhypoxia preconditioning that has been reported in the literature, inwhich survivability in 5% O₂ was extended only twofold (Zhang et al.2004). Although not shown in FIG. 23, some H₂S pre-treated mice wereable to survive for more than four hours in 5% O₂ and were able torecover with no noticeable motor or behavioral deficits.

To determine if H₂S pre-treatment enhances survivability to even loweroxygen tensions, mice were exposed to lower O₂ concentrations. As shownin FIG. 24, H₂S pre-treatment greatly enhances survival in the presenceof 5% O₂. In contrast, H₂S pre-treatment provided only a small increasein survival in the presence of 4% O₂. However, if H₂S pre-treated micewere exposed to a step-wise reduction in O₂ levels, such that they werefirst pre-treated and then exposed for 1 hour to 5% O₂ and then exposedto either 4% O₂ or 3% O₂, their survival time was enhanced to the samelevel as that observed when they were exposed to 5% O₂ following H₂Spre-treatment (FIG. 28). Thus, pre-exposure to H₂S establishes aphysiological state in which mice can survive a graded reduction inoxygen tensions exceeding 80% (21% normoxia reduced to 3% O₂).Furthermore, in some experiments, graded reduction of oxygen tensionfollowing H₂S pre-treatment showed the mice can survive for an hour inoxygen tensions as low as 2.5%.

These data and those described in Example 7 demonstrate that exposure toH₂S has a pharmacological effect in which survival in otherwise lethalhypoxia is greatly enhanced. In this context, the pharmacologicaleffects of H₂S depend on dose levels and duration of exposure to H₂S,parameters that one skilled in the art can vary to achieve optimumsurvivability to lethal hypoxia. One skilled in the art will appreciatethat the route of administration (e.g., inhaled versus parenteraladministration) can also be varied to achieve the desired effect oflethal hypoxia tolerance in a mammal. In addition, the pharmacologicaleffect can be observed either when H₂S exposure is limited topre-treatment or is extended into the period of hypoxia. Likewise, thetiming of exposure to H₂S relative to the onset of lethal hypoxia can bevaried to maximize the enhanced survivability. These data are consistentwith the hypothesis that reduction in oxygen demand resulting frompretreatment with an active compound, such as an oxygen antagonist,allows survival in reduced oxygen supply that is otherwise lethal to theanimal.

To characterize the changes in metabolism that occur in the setting ofenhanced survivability to lethal hypoxia afforded by H₂S treatment, CO₂production by the mice was measured during exposure to H₂S andthereafter following termination of H₂S treatment and subsequentexposure to 5% O₂. The change in CO₂ production is shown in FIG. 25.Changes in CO₂ production upon transition to either 5% O₂ or 4% O₂ weremeasured in mice exposed to either room air for 30 minutes (No PT) orroom air for 10 minutes followed by 150 ppm H₂S for 20 minutes (PT). Inaddition, the change in CO₂ production upon step-wise transition to 5%O₂ for 1 hr followed by 4% O₂ was measured. The results of theseexperiments are provided in FIG. 29.

CO₂ production was reduced approximately two to three-fold in the firstfive to ten minutes of H₂S pre-treatment, suggesting that stasis isinduced in the mice during the minute pre-treatment with 150 ppm H₂S inroom air. However, O₂ consumption and core body temperature of theanimals did not change significantly during the H₂S pre-treatment (datanot shown), suggesting that a physiological state other than stasis maybe established in the mice during exposure to H₂S that allows enhancedsurvivability to lethal hypoxia. Such a state might be characterized bya reduction in metabolism within the biological material of a magnitudethat is less than that defined as stasis. In order to achieve stasisusing an active compound, the biological matter necessarily musttransition through a graded hypometabolic state in which oxygenconsumption and CO₂ production are reduced less than twofold in thebiological matter. Such a continuum, in which metabolism or cellularrespiration is reduced by an active compound to a degree less thantwofold, is described as a state of “pre-stasis.” Continued monitoringof CO₂ production following termination of H₂S pre-treatment andinduction of lethal hypoxia shown in FIG. 25 demonstrates anapproximately 50-fold reduction in CO₂ production, indicating thatstasis is achieved during the exposure to lethal hypoxia. A concomitantdecrease in O₂ consumption and strong attenuation of motility in themice during exposure to lethal hypoxia further supports the observationthat stasis is subsequently achieved during exposure to lethal hypoxia.

Changes in CO₂ production associated with transition to hypoxicconditions of either 5% O₂ or 4% O₂ after H₂S pre-treatment or nopre-treatment were measured. As shown in FIG. 28, mice exposed to either5% O₂ in the absence of H₂S pre-treatment or exposed to 4% O₂ in thepresence of H₂S pretreatment displayed a substantial decrease in CO₂production. In contrast, H₂S pre-treated mice that were subsequentlyexposed to either 5% O₂ or 5% O₂ followed by 4% O₂ did not show anysignificant changes in CO₂ production as compared to the new baselinelevel following H₂S pre-treatment. These results demonstrate acorrelation between reduced metabolic activity and death associated withexposure to 5% O₂ in the absence of H₂S pre-treatment or exposure to 4%O₂ with H₂S pre-treatment. In addition, these data demonstrate thatexposure to 5% O₂ or a step-wise reduction from 5% O₂ to 4% O₂ followingH₂S pre-treatment does not result in an additional reduction inmetabolic activity. To summarize these results, decreases in CO₂evolution that occur upon transition form normoxia to lethal hypoxiawere blunted in mice that were pre-treated with H₂S. Transition fromnormoxia to lethal hypoxia caused a 40% reduction in CO₂ evolution, butpre-treatment with H₂S, while itself causing a 50-60% reduction in CO₂evolution to a new, lower baseline, prevented any further decrease inCO₂ evolution on transition to lethal hypoxia. These data demonstratethat H₂S pretreatment alone prevents additional reductions in metabolicactivity typically associated with a transition to lethal hypoxia,thereby enhancing survival under hypoxic conditions. In addition, thesedata support a model wherein pre-exposure of biological matter to activecompounds is sufficient to enhance survivability and/or reduce damagefrom injuries or disease insults.

Example 12 Hydrogen Selenide Reduces Core Body Temperature in Mice atReduced Concentrations

It had been previously reported in the literature that greater than 1ppm of H₂Se was lethal to animals. Experiments were conducted accordingto the Materials and Methods discussed in Example 4, except that H₂Sewas used at even lower concentrations than with H₂S. The H₂Se used hadan initial concentration from the source tank of 20 ppm in nitrogen,which was then diluted with room air to approximately 10 or 100 partsper billion (ppb). Animals were then exposed to this mixture.

Two mice were exposed to 100 ppb H₂Se for less than 10 minutes. FIG. 26shows the drop in core body temperature and 3-fold reduction inmetabolic activity as evidenced by respiration in one mouse.

The concentration of H₂Se was reduced even further to 10 ppb. A mouseexposed to 10 ppb of H₂Se also experienced a reduction in core bodytemperature and respiration (FIG. 27).

Moreover, the effects of H₂Se appear fully reversible based on testsused to evaluate reversibility with H₂S (Blackstone et al., 2005, whichis hereby incorporated by reference).

Example 13 Hydrogen Sulfide Protects Against Lethal Hemorrhage

The studies shown in Examples 7 and 11 demonstrated that treatment ofmice with hydrogen sulfide (H₂S) enhances their ability to survive underhypoxic conditions of 5% oxygen or 4% oxygen. To determine whether H₂Streatment could also be used to reduce morbidity and/or tissue damageassociated with a more clinically relevant acute injury model ofischemic hypoxia, rats were treated with H₂S during controlled lethalhemorrhage, which reduces oxygen supply to tissues and results in death(Blackstone et al., 2005). In this study, rats treated with H₂S survivedlethal blood loss and fully recovered.

Rats were treated with H₂S during controlled lethal hemorrhage (60%blood loss). After surgical implantation of catheters and recovery,blood was removed from conscious animals in 40 minutes. A small amount(300 ppm) of H₂S mixed with room air was administered to treated animalstwenty minutes after the beginning of the bleed (i.e., after 30% bloodloss). Animals were returned to room air without H₂S at the end of thebleed. Three hours after the end of the bleed, surviving animals weregiven one shed-blood volume of lactated ringers solution intravenously.

Most (6/7) of the H₂S treated rats survived hemorrhage and 3 hour shockperiod and recovered completely (Table 7). None of these surviving ratsexhibited behavioral or functional defects after recovery. One H₂Streated animal died 174 minutes after the end of the bleed. All of theuntreated animals died within 82 minutes after the end of the bleed;average survival time of untreated animals was 35+/−26 minutes. Using atwo-tailed Fishers exact T-test, the p value is 0.0047.

In the first twenty minutes of bleeding (before 30% blood loss) ratsincreased respiration rate and tidal volume to compensate for decreasedoxygen carrying capacity due to blood loss. This increase in ventilationresulted in a decreased respiratory carbon dioxide production (V_(CO2))(Table 7). After 60% blood loss, both H₂S treated and untreated animalsexhibited decreased V_(O2). Arterial blood lactate increased while pCO₂,bicarbonate ([HCO₃ ⁻]), pH, and base excess decreased (Table 7). Thushemorrhage resulted in metabolic acidosis with respiratory compensation.However, in H₂S treated rats, these changes were smaller in magnituderepresenting a decrease in metabolic acidosis. Furthermore, in H₂Streated animals, V_(CO2) did not continue to decrease after hemorrhage.In untreated animals, V_(CO2) decreased steadily until the animalsstopped breathing. H₂S administration appears to prevent the shockresponse from progressing to death

TABLE 7 Survival and physiology of a rat hemorrage model using H₂S H₂STreated Untreated Survival Complete recovery 85.7% (6/7) 0% (0/7) Timeto death of non-survivors (min) 174 (1/7)  35 +/− 26 CO₂ production(V_(CO2)) in ml/kg/min: Pre-bleed 25 +/− 4 26 +/− 6 Mid-bleed 20 +/− 221 +/− 3 End of bleed 16 +/− 2 11 +/− 3 15 minutes post bleed 17 +/− 3 7 +/− 5 Blood CO₂ content (pCO₂) in mmHg Pre-bleed 45 +/− 6 44 +/− 3End of bleed 35 +/− 6 21 +/− 3 Blood bicarbonate content ([HCO₃ ⁻]) inmmol/L Pre-bleed 32 +/− 3 30 +/− 1 End of bleed 21 +/− 3 12 +/− 3 BloodpH Pre-bleed  7.46 +/− 0.03  7.45 +/− 0.02 End of bleed  7.41 +/− 0.02 7.35 +/− 0.06 Blood base excess in mmol/L Pre-bleed  8 +/− 2  6 +/− 1End of bleed −5 +/− 4 −14 +/− 3  Blood Lactate in mmol/L Pre-bleed  1.4+/− 0.5  1.2 +/− 0.2 End of bleed 6.6 +/− 1  11 +/− 3

Example 14 Benefit of Short-Term Exposure to Hydrogen Sulfide DuringHemorrhage

Male Sprague Dawley rats weighing 275-350 grams were purchased fromCharles River Laboratories one week before each experiment and allowedto acclimate. On the day of the experiment, catheters were surgicallyimplanted into the right femoral artery and vein. Catheters exitedbehind scapulae. Rats were administered buprenorphine post-surgicallyand allowed to recover.

The anti-coagulant drug heparin (80-100 units) was administeredintravenously as a bolus to decrease the clotting ability of the bloodand enhance hemorrhage. Following heparin administration, consciousunrestrained rats were placed individually in a 2.75 litercrystallization dish with a glass lid. Catheters, temperature probe, andgas sampling tube were passed through a hole drilled in the middle ofthe lid. Temperature was maintained at approximately isothermaltemperature (27+/−2° C.).

The hemorrhage model was defined by the removal of 60% of total bodyblood over the course of a 40 minute bleed. Blood was removed using aperistaltic pump. To determine the amount of blood that constitutes 60%of total body blood, rats were weighed and the volume of blood to wascalculated using the following equation (0.06×body mass)+0.77 (Lee etal., (1985).

Treatment groups received exposure to either room air with hydrogensulfide (test animals), or room air containing nitrogen (controlanimals) at a rate of 3 liters per minute administered by a thermal massflow controller (Sierra Instruments).

Hydrogen sulfide (H₂S) (20,000 ppm balanced with nitrogen) (ByrneSpecialty Gas) was diluted into room air to a concentration of 2000 ppmfor treatment. Blood was removed at the calculated rate via the femoralcatheter artery. Blood was weighed as it was removed. After twentyminutes (or at 50% of the 40 minute bleed) the test animals were exposedto room air containing 2000 ppm hydrogen sulfide. The exposure wasterminated when animals exhibited apnea and dystonia. The average lengthof exposure to hydrogen sulfide (H₂S) was generally between 1 and 2minutes. The maximum concentration of H₂S in the chamber was estimatedto be between 1000 and 1500 ppm. When the apnea and dystonia wereobserved, the animals received exposure to room air. Test animalsresumed regular breathing patterns within 20 to 30 seconds uponexposure. Control animals were bled at the same rate as the testanimals, but did not receive treatment with hydrogen sulfide. Controlanimals did not exhibit apnea or dystonia during the course of theexperiment.

Metabolic rate was determined by measuring CO₂ production (LicorLi7000). Temperature and CO₂ data were collected (ADI PowerLab).Arterial blood values were measured (1-Stat blood chemistry analyzer).Following the bleed, animals were placed in a cage for three hours andobserved. At the end of three hours, surviving rats were given lactatedringers ad libitum. For non-surviving animals, time of death wasdeclared when animals stopped breathing and CO₂ production ceased. Afterresuscitation, rats were transferred to clean cages with food and waterand housed at 30° C. for approximately 16 hours. Catheters weresurgically removed and animals were allowed to recover for several hoursat 30° C. before transfer back to the colony. Behavior and functiontests were selected from a battery of tests described in the SHIRPAprotocol (Rogers et al., 1997).

In these experiments, 7 out of 8 (88%) of the animals treated withhydrogen sulfide (H2S) during the course of the hemorrhage survived thehemorrhage. Two control animals who did not receive treatment diedduring the three hour observation period.

Example 15 Additional Results from Example 2

As discussed in Example 2 above, human foreskins were used to evaluatedthe preservation of cells and tissue in carbon monoxide. A total ofeight human foreskins were ultimately evaluated (Example 2 reports onthree). The number of viable keratinocytes was evaluated using trypanblue (Table 8 and FIG. 30). This showed that carbon monoxide exposureincreased the number of viable cells.

TABLE 8 Viability of keratinocytes isolated from Foreskins exposed toeither room air (RA) or CO for 24 hours were tested for viability usingtrypan blue (tb) staining. RA CO fraction live dead fraction live (tb−)dead (tb+) alive (tb−) (tb+) alive 0 3 0.00 10 1 0.91 1 1 0.50 4 4 0.500 0 10 3 0.77 0 0 5 1 0.83 7 34 0.17 49 42 0.54 0 1 0.00 24 6 0.80 1 20.33 3 3 0.50 0 1 0.00 1 1 0.50 SUM 9 42 0.18 106 61 0.63 # cellsrecovered fraction alive untreated 51 0.18 ttest 0.000883884 CO 167 0.63

Example 16 Low Level Chronic H₂S Exposure Increases Survivability

Using methods and apparatus described in Example 1, C. elegans nematodeswere exposed to low levels of H₂S (<100 ppm). Nematodes adapted to thistreatment exhibit increased lifespan and resistance to thermal stress,however, there is no discernable decrease in metabolic activity as withinduction of stasis.

In nematodes, the inability to perform aerobic metabolism (by reducingambient oxygen concentration or addition of CO) results in the inductionof suspended animation, or stasis (see Example 1). However, suspendedanimation was not induced by exposing them to <100 ppm H₂S in house air.At doses above 100 ppm, H₂S can result in considerable lethality of thepopulation of nematodes exposed. Interestingly, even in conditions wherethe majority of worms are killed by H₂S, those that survive appearnormal and are not obviously harmed by the agent. The worms growing inapproximately 50 ppm H₂S complete embryogenesis, develop to sexualmaturity and produce progeny at the same rate as siblings raised inenvironments without H₂S. In contrast, in concentrations of oxygen wheremetabolic rate is reduced (less than 3.5% O₂), all of these processesare slowed. Moreover, worms raised in H₂S produce the same number ofprogeny as controls in house air, suggesting that there are nodeleterious effects from these conditions. These data indicate that H₂Sdoes not reduce metabolic activity under these conditions in C. elegans.

Nematodes grown in H₂S are more resistant to heat stress thanage-matched controls in house air alone (FIG. 31). In this assay, wormsraised in 50 ppm H₂S were exposed to high temperature in H₂S and wormsraised in house air were exposed in house air. Thus, H₂S-inducedresistance to stress is not correlated with decreased metabolicactivity. However, this resistance to heat-stress requires that thenematodes be adapted to the H₂S environment. Worms raised in house airand exposed to heat-stress in H₂S die more rapidly than if they wereexposed in house air. The adaptation to H₂S is persistent, insofar asworms raised in H₂S and exposed to heat stress in house air survivebetter than controls raised in house air. In addition, worms adapted toa non-toxic low concentration of H₂S (e.g., 50 ppm) were resistant tohigher concentrations of H₂S that are lethal to unadapted worms.

These data are consistent with data that flies transiently exposed toH₂S are subsequently able to survive anoxia better than untreatedcontrols (e.g., Example 7 and Example 11). The protection against heatstress (in worms) and anoxic stress (in flies) suggests that H₂S may beable to increase survivability in a variety of adverse or stressfulstates that may be encountered clinically.

Worms adapted to 50 ppm H₂S also have increased lifespan compared toisogenic untreated controls (FIG. 32). This is consistent with the ideathat they are in a state that is generally more resistant to variousstresses associated with aging. In fact, old worms grown in H₂S seemmore vigorous and healthy than those of similar age not treated withH₂S. Moreover, this is also true when comparing worms from eachpopulation at the midpoint of lifespan (i.e., the house air controls andH₂S-treated worms are not chronologically age matched, but the pointwhere 50% of each population has died). Thus, adaptation to H₂S may slowchronic cellular damage associated with aging in C. elegans.

Example 17 Implementation of Gas Matrix Experiments

Metabolic flexibility was evaluated in mice rats and dogs using alteredgas environments. Three parameters were used to define this reduction inmetabolism including changes in carbon dioxide production, oxygenconsumption measured by respirometry, and core temperature as measuredusing telemetry. In experiments with mice and rats the animals wereplaced into sealed chambers with one gas import and one gas export. Fordogs a mask was placed over the snout of the animal with two hoses(import and export) attached to the mask. The flow rate of gas for eachof the animals mice-500 cc per minute, rats-2 liters per minute, anddogs 40 liters per minute. Each atmosphere was constructed fromcompressed gas by dilution into room air unless otherwise noted. For ratand mouse experiments the ambient temperature was 7 to 10° C. duringexposure to the test gases. For dogs ambient temperature was roomtemperature (22° C.).

TABLE 9 Description of gas environments constructed to test formetabolic flexibility in mice rats and dogs. Mouse Rat Dog Hydrogensulfide Yes 0.01% Yes 0.03% No 0.85% Hydrogen Yes 0.0001% Yes 0.003% N/Dselenide Phosphine No 0.016% N/D N/D Carbon dioxide Yes 15% Yes 15% No9% H₂S + CO₂ Yes 0.01% + 15% N/D N/D CO₂ + low O₂ Yes 15% + 8% Yes 15% +8% N/D CO₂ + low O₂ + Yes 15% + 8% + Yes 15% + Yes 9% + He 77% 8% + 77%15% + 77%

Table 9 shows the amount of each gas, which is given as a percentage ofthe room air atmosphere unless otherwise noted. Evidence of depressionin metabolic rate of greater than 5-fold as judged by carbon dioxideproduction or oxygen consumption during a 6-hour treatment is describedby “Yes”; “No” (reduction or less than a 5-fold reduction in thesevalues is described as such; “N/D” denotes experiments not done. Thetemperature drop in the dog experiment (Carbon dioxide+lowoxygen+Helium) was approximately 1.5° C. over the course of 30 minutesof exposure. This drop in temperature was considered significant becausethe dog was 12 kg and no such temperature drop was seen during extensivebaseline recording of the animal in room air.

Animals exposed to various constructed atmospheres exhibited metabolicflexibility as demonstrated by changes in core body temperature (CBT)that approach ambient temperature (FIGS. 33-40). FIG. 33 demonstrates arat exposed to an atmosphere containing 15% CO₂, 8% O₂, and 77% He has ametabolic depression that is accelerated compared to a rat exposed to300 ppm H₂S under similar conditions. FIG. 34 demonstrates a significantdrop in CBT of a mouse exposed to 1.2 ppm of H₂Se. Rats exposed to roomair at an ambient temperature of 110° C. do not show significant drop inCBT (FIG. 35), nor do rats exposed to 80% He, 20% O₂ at 7° C. (FIG. 36).Rats exposed to an atmosphere of 15% CO₂, 20% O₂, 65% He at an ambienttemperature of 7° C. show significant drop in CBT (FIG. 37). Similarly,FIG. 38 shows a significant CBT drop in a rat exposed to an atmosphereof 15% CO₂, 8% O₂, 77% He at 7° C. A significant drop in CBT was alsodemonstrated in a dog exposed to an atmosphere of 9% CO₂, 20% O₂, 71% He(FIG. 39). The magnitude of the drop is lower, presumably because of thelarger size of the animal and the limitations of thermal diffusion. Asimilar drop is seen in a dog exposed to different concentrations ofCO₂.

Example 18 Screening of Compounds

A compound screen was performed to identify test compounds capable ofcausing a reversible drop in subcutaneous temperature in a mouse.Identified test compounds were then tested for their ability to provideprotection against lethal hypoxia (measured at 4% O₂ as opposed to atypical environment of 21% O₂ balanced nitrogen environment). The entirescreening procedure involved three steps:

1) a primary (10) screen to determine the minimum effective dose of atest compound that would produce a measurable drop in a test mouse'ssubcutaneous temperature;

2) a secondary (2°) screen to determine the reversibility of thetemperature drop, as defined by the test mouse having normal behavior 24hours after treatment and having returned to normal subcutaneoustemperature in 24 hours or less; and

3) atertiary (3°) screen to assess the ability of the test mouse tosurvive lethal hypoxia (4% O₂) as compared to an untreated controlsubject under identical hypoxic conditions.

The mice used in these studies were male C57BL/6 jugular veincatheterized (JVC) mice, 5-6 weeks old (Taconic), which were implanteddorsally with a subcutaneous RFID temperature sensor (IPTT-300, BioMedic Data Systems, Inc. (BMDS)) and allowed to recover for at least 24hours. The mice were dosed through the in-dwelling catheter with theinfusion of test compound using 1 or 5 ml Luer-Lok syringes (BectonDickinson) and an infusion pump (Harvard Apparatus). A DAS-6008 dataacquisition module from BMDS recorded subcutaneous temperature of themouse via the transponder, and this data was input into a computerspreadsheet and plotted against time.

Primary (1°) Screen:

For the primary screen, the infusion of test compound was made up at aconcentration that was considered to be the maximum optimizedconcentration. The pH was adjusted with NaOH or HCl to 6-8, theosmolarity was adjusted with sodium chloride to 250-350 mOsm and thetotal dose of test compound to be administered (in mg) divided by thetest subject's weight (in kg) did not exceed 400% of its published mg/kgLD50 in a mouse.

Mice were placed into a tall glass-bottom jar with opaque walls andinfused via the jugular vein. The test compound was infused using a stepprotocol with increased infusion rates over 2 hours (Table 10).

TABLE 10 Test Compound Infusion Step Protocol infusion time (min) rateμL/min microliters infused microliters infused total  0-20 0.8 15.87515.875 20-40 1.6 31.75 47.625 40-60 3.2 63.5 111.125 60-80 6.3 127238.125  80-100 12.7 254 492.125 100-120 25.4 508 1000.125

During the infusion, the mouse subcutaneous temperature was read every3-5 minutes, and any changes in the mouse behavior were recorded. Theresults of the primary screen revealed whether the test compound had theability to lower subcutaneous temperature to 33° C. or lower, andindicated the effective dose required to lower subcutaneous temperatureas measured by the infusion rate of the test compound at which a steadytemperature drop was first observed.

Secondary (2°) Screen:

Test compounds that produced a decrease in mouse subcutaneoustemperature to 33° C. or below were tested in the secondary screen. Inthe secondary screen, the mouse was infused with test compound for 60minutes at a rate of 50% of the effective infusion rate determined inthe primary screen. During the infusion, the mouse subcutaneoustemperature was monitored by taking measurements every 3-5 minutes. Ifthe subcutaneous temperature did not decrease in the first 60 minutes,the infusion rate was doubled and continued for another 60 minutes. Whenthe mouse subcutaneous temperature decreased to 33° C. or below, theinfusion was immediately stopped, and the mouse recovery was assessed bymeasuring subcutaneous temperature and observing the mouse behavior. Themouse temperature and behavior were observed and recorded 24 hours aftertreatment. The result of the secondary screen determined if the testcompound caused a reversible drop in subcutaneous temperature withoutlethality.

Tertiary/lethal hypoxia (3°) screen: In the tertiary screen, the mousewas infused with test compound at the rate determined in the secondaryscreen. The mouse subcutaneous temperature was measured every 3-5minutes until it decreased to 33° C., as in the secondary screen. Theinfusion was stopped and the mouse was immediately transferred to ahypoxic chamber (4% O₂), together with a control mouse, either infusedwith vehicle (salt solution, 148 mM, osmolarity=300), or untreated. Theclosed glass chamber was perfused with air and nitrogen at a continuousflow to achieve the desired hypoxic atmosphere of 4% O₂. If the mousesurvived 60 minutes in the hypoxic atmosphere, it was transferred backto room air, and its recovery was monitored for 24 hours by recordingthe subcutaneous temperature and by behavioral observation.

The control mouse typically died within 6-15 minutes.

Mice infused with either sodium sulfide (effective dose 0.79 mmol/kg),sodium thiomethoxide (effective dose 4.61 mmol/kg), or sodiumthiocyanate (effective dose 4.67 mmol/kg) survived exposure to lethalhypoxia for 60 minutes. A mouse infused with cysteamine (effective dose7.58 mmol/kg) survived in lethal hypoxia for 45 minutes; a mouse infusedwith cysteamine-5-phosphate sodium salt survived in lethal hypoxia for31 minutes; and a mouse infused with tetrahydrothiopyran-4-ol survivedin lethal hypoxia for 15 minutes. These survival rates are compared tothe survival rate of a control mouse, which typically died within 6-15minutes in the hypoxic environment.

In comparison, certain other test compounds identified in the primaryscreen as having the ability to lower body temperature did not protectfrom lethal hypoxia. Thioacetic acid, selenourea, and phosphorothioicacid S-(2-((3-aminopropyl)amino)ethyl) ester all reduced bodytemperature, but did not enhance survival in hypoxia.2-mercapto-ethanol, thioglycolic acid, and 2-mercaptoethyl ether allreduced body temperature but were toxic at the effective temperaturereducing dose. Thiourea, dimethyl sulfide, sodium selenide, sodiummethane sulfinate, N-acetyl-L-cysteine did not reduce subcutaneoustemperature at the highest doses given in this study. Dimethylsulfoxidewas excluded because the effective dose (10% DMSO) was too high to beconsidered for pharmaceutical purposes.

These studies establish that the screening procedures developed may besuccessfully used to identify compounds capable of protecting animalssubjected to lethal hypoxia. In addition, the results of this studiesindicate that the identified compounds, as well as other compounds to beidentified using this procedure, may be used to protect patients frominjury resulting from hypoxic and ischemic injury.

Example 19 Daily Exposure to Active Compound

The ability to adapt physiologically to extended treatment with hydrogensulfide (H₂S) and the time required for adaptation was tested in amouse. Adaptation was defined as a failure to exhibit a decrease in corebody temperature (greater than 4° C.) when an animal was exposed to 80ppm of hydrogen sulfide in room air for an extended treatment. Extendedtreatment was defined as exposure to 80 ppm of hydrogen sulfide in roomair for four hours per day, four days per week for six weeks.

The mice used in these studies were male C57BL/6 mice or male C129 mice,5-6 weeks old. Telemetry devices were implanted into the coelomic cavityof the mice prior to the experiments to record core temperature.

Mice (eight per treatment) were exposed to hydrogen sulfide in a singleplexiglass box with separate chambers for each mouse at a flow rate was10 liters per minute. Detection of carbon dioxide production and oxygenconsumption animals in 500 cc glass bowls had flow rate of 0.5 litersper minute.

Mice adapted to hydrogen sulfide exposure on average, in a one weekperiod. Adaptation was defined by a failure to exhibit a decrease(greater than 4° C.) in core temperature when animals were exposed to 80ppm of hydrogen sulfide in room air for 4 hours. Mice that did notexhibit a drop in core temperature were deemed to have a physiologicaladaptation to hydrogen sulfide. Mice treated with hydrogen sulfide thatdeveloped an adaptation showed an increase in oxygen consumption (vO2)compared to carbon dioxide production (vCO2) when compared to untreatedcontrol mice (FIG. 42). Mice with an adaptation to H₂S showed a lowerRespiratory Quotient (RQ ratio), defined as the ratio of vCO2/vO2 or acomparison of produced carbon dioxide to consumed oxygen (FIG. 43).

Example 20 Applications for Thalassemia

Based on the current results in other model systems presented here, itexpected the red blood cells of animals with the hematological disorder,thalassemia, will have an increased ability to withstand oxidativedamage, leading to prolonged red cell survival when they are treatedwith sulfides. The following experiments will be performed to confirmthat treatment with active compounds can protect animals withthalassemia from oxidate damage.

In a first series of experiments, animals with thalssemia will betreated by chronic exposure to an active compound. After initial teststo establish baselines, treatment will be initiated following theprotocol summarized below. If erythropoiesis or red cell survival areimproved, an effect may be observed in as early as 1-2 weeks, since thehalf-life of thalassemic red cells is estimated at 4-7 days. We willreview a smear and obtain a reticulocyte count at two weeks, andinitiate more extensive studies after an additional two weeks. If animprovement in the red blood cells is determined in mice, as identifiedby an improved reticulocyte count and blood smear, the study willcontinue until a plateau is observed in the metrics used in the monthlystudies. This study has a projected final end point of one year. At oneyear, red cell survival studies will be completed, and the animals willbe sacrificed. If no improvement is observed, exposure will continue forup to one additional year, when survival studies will be accomplishedand the animals sacrificed.

Protocol 1:

1) Animals will undergo initial studies.

2) Within one week after initial studies, animals will be housedidentically and either:

-   -   A) exposed to 80 ppm H₂S for 8 hours/day;    -   B) no exposure; or    -   C) given water with 0.25% dimethyl sulfide (DMSO) and allowed to        drink ad lib (estimates from prior studies suggest mice will        consume 5-10 cc/day/mouse with 2.5-25 microgram/day DMSO        content. Using an average weight of 18 g per mouse, consumption        is estimated to be 700-1,400 ug/kg/day).

In a second series of experiments, the effect of in utero treatment withan active compound will be determined, following the protocol summarizedbelow.

Protocol 2:

1) Plugged dams will be treated in one of the following groups threedays post conception:

-   -   A) exposed to 80 ppm H₂S for 8 hours/day;    -   B) no exposure; or    -   C) Given water with 0.25% dimethyl sulfide (DMSO) and allowed to        drink ad lib (estimates from prior studies suggest mice will        consume 5-10 cc/day/mouse with 2.5-25 microgram/day DMSO        content. Using an average weight of 18 g per mouse, consumption        is estimated to be 700-1,400 ug/kg/day).

2) Plugged dams will be allowed to give birth naturally, and pups willbe genotyped and sacrificed for detailed analysis soon after birth.

The test animals will be monitored throughout these studies as indicatedbelow.

Monitoring:

-   -   1) Initial studies:    -   1. reticulocyte count;    -   2. blood smear    -   3. Computed Tomography (CT scan) of spleen and bones;    -   4. O₂ consumption and CO₂ production;    -   5. weight;    -   6. sulfide metabolites and    -   7. hematocrit (60 μl blood total).

2) At two weeks: reticulocyte count and blood smear (5 μl blood).

3) Monthly studies:

-   -   1. reticulocyte count;    -   2. CT of spleen and bones;    -   3. O₂ consumption and CO₂ production;    -   4. weight; and    -   5. sulfide metabolites (blood draw will be less than 30 μl).

4) One month prior to sacrifice: red cell survival studies.

5) Sacrifice and detailed in vitro analysis.

Example 21 Applications for Sickle Cell Anemia

To test this hypothesis, a mouse model of sickle cell disease (SCD) willbe used in which the strain was engineered so that it no longerexpresses mouse Hba and Hbb, but does express human HBA and HBB (Patsy,et al, 1997). It mimics the genetic, hematologic and histopathologicfeatures that are found in humans afflicted with sickle cell anemia,including irreversibly sickled red blood cells, anemia and multiorganpathology. A significant percentage of sickle cell mice do not surviveto adulthood.

Using this mouse model, various agents and sulfide containing compoundswill be tested for efficacy against SCD. Exposures will be acute andchronic, and animals will be exposed either at birth or in utero.Viability to birth for pups exposed in utero or to adulthood will be oneendpoint to measure efficacy. Phenotypic effects will be evaluatedthrough reticulocyte count, hematocrit and red blood cell (RBC)half-life measurements (which are normally 20 fold less for SCD comparedto wild type controls).

Example 21 Cyanide Exposure Experiment

This example shows that when mice are exposed to 80 ppm of cyanide inroom air they gradually reduce their core temperature to about 34° C.

One goal of these metabolic flexibility studies has been theidentification of compounds that can reduce oxygen consumption andprotect animals from hypoxic injury. Previously, it was demonstratedthat Hydrogen Sulfide (H₂S), a potent inhibitor of oxygen consumption,can reduce metabolism and protect mice and rats from hypoxic injuries.Hydrogen Cyanide (HCN) is similar to H₂S in many ways and we would liketo use our assays of metabolic output to learn if it can be used toregulate metabolism. Like H₂S, HCN is widely used in industrial chemicalsyntheses and it is found in many biological systems including humans.It is not known if HCN is merely a byproduct of carbon-nitrogenmetabolism or if it possesses specific biological activities. Like H2S,HCN is thought to act by reacting with transition metal containingproteins such as oxidases and dehydrogenases. HCN is not stronglyreactive with components of hemoglobin.

In humans, the NIOSH IDLH (immediately dangerous to life and health)value is 50 ppm. The OSHA PEL (permissible exposure limit) TWA (timeweighted average for 8 hours) is 10 ppm. The LC50 for rat is 143 ppm for60 minutes.

To measure metabolic effects of HCN, mice were exposed to increasingconcentrations of HCN starting at 1 ppm. Oxygen (O₂) consumption, carbondioxide (CO₂) production, body core temperature (BCT) and behavior weremeasured or evaluated. The concentration of HCN was raised by 10 ppmincrements until an effect on metabolism was observed or when theanimals appeared to show signs of distress. A metabolic effect isdefined as a 10% change in less than 10 minutes in any of the assayvalues described above.

It was found that when mice were exposed to 80 ppm of cyanide in roomair at room temperature they gradually reduced their core temperature toabout 34° C. This is distinct from the decrease seen with 80 ppmhydrogen sulfide where the core temperature drops to approximately 28degrees C. In addition, there was a very slow recovery of the coretemperature in mice exposed to cyanide (approximately 14 hours) comparedto hydrogen sulfide (approximately 2 hours).

The hypothesis was tested that the slow recovery, as judged by coretemperature, in cyanide could be rescued by brief exposure to 80 ppmhydrogen sulfide. This was based on the idea that, a conserved enzyme,rhodanese (and other similar enzymes), might use hydrogen sulfide andcyanide to produce the relatively less toxic agent, thiocyanate. Alreadyit has been shown that rhodanese can use cyanide and thiosulfate toproduce thiocyanate. (Chen 1933) Furthermore, intravenous administrationof thiosulfate is the standard of care for treating cyanide intoxicationin the US. It was found that the time to recover the core temperaturefollowing exposure to cyanide was reduced by brief treatment withhydrogen sulfide. This result suggests that hydrogen sulfide exposuremight be used to treat conditions in which patients suffer from cyanideintoxication.

All of the compositions and methods disclosed and claimed herein can bemade and executed without undue experimentation in light of the presentdisclosure. While the compositions and methods of this invention havebeen described in terms of preferred embodiments, it will be apparent tothose of skill in the art that variations may be applied to thecompositions and methods, and in the steps or in the sequence of stepsof the methods described herein without departing from the concept,spirit and scope of the invention. More specifically, it will beapparent that certain agents which are both chemically andphysiologically related may be substituted for the agents describedherein while the same or similar results would be achieved. All suchsimilar substitutes and modifications apparent to those skilled in theart are deemed to be within the spirit, scope and concept of theinvention as defined by the appended claims.

REFERENCES

The following references, to the extent that they provide exemplaryprocedural or other details supplementary to those set forth herein, arespecifically incorporated herein by reference.

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1. A method for enhancing survivability of biological matter comprisingproviding to the biological matter an effective amount of at least oneactive compound.
 2. The method of claim 1, wherein the active compoundis an oxygen antagonist.
 3. The method of claim 1, wherein the matter isexposed to the active compound.
 4. The method of claim 1, wherein theactive compound is a chalcogenide.
 5. The method of claim 1, wherein theactive compound has a chemical structure of Formula I or Formula IV. 6.The method of claim 5, wherein the matter is exposed to a precursor of achemical structure of Formula I or Formula IV.
 7. The method of claim 1,wherein the matter is provided with a combination of active compounds.8. The method of claim 1, wherein the matter is provided with the activecompound before, during, or after an injury, the onset or progression ofa disease, or hemorrhaging in the matter.
 9. The method of claim 8,wherein the injury involves hemorrhaging.
 10. The method of claim 9,wherein the injury is from an external physical source.
 11. The methodof claim 8, wherein the active compound is provided before the injury orbefore the onset or progression of the disease.
 12. The method of claim8, wherein the injury or disease is associated with a reduction inmetabolism or temperature of the matter.
 13. The method of claim 12,wherein the injury is a surgery. 14.-149. (canceled)